Hosta ‘Francis Williams’ and others play off well aginst ferns in this shade garden
Asparagaceae
hosta, plantain lily
This genus regularly lists at or near the top in perennial popularity polls, and no wonder. Hostas flourish from USDA zones 3 through 8, with a few of the more heat-tolerant types performing satisfactorily in the cooler parts of zone 9. Although moisture loving, with conscientious irrigation the more resilient cultivars can survive the drought-prone summers of the prairie and Rocky Mountain states.
Hostas’ chief attraction is their foliage, borne in neat circular clusters of broad leaves with parallel veins that may be colored gold or blue as well as green, and striped, edged, or splashed with white or some other contrasting color. Foliage texture varies from shiny and smooth to pleated, puckered, and waxy, and individual leaves may measure from 1–20 in. long and 0.75–12 in. wide. The flowers of most species and cultivars are unremarkable; borne in summertime in terminal racemes atop erect scapes. The blossoms are lily-like, typically pendulous, 0.75–2 in. long, with six petal-like tepals, in shades of white, lavender, or violet. One exception to the rule is Hosta plantaginea, whose white flowers are not only fragrant—it’s the only species with this characteristic—but also measure up to 6 in. long. Plant breeders are currently focusing on hosta cultivars with more attractive and fragrant flowers.
Often categorized as a “shade plant,” hostas offer some of the best choices for lower-light situations, though most prefer partial shade, and none flourish in deep, unrelieved shade, especially the dry shade found beneath conifers and shallow-rooted deciduous trees such as maples. In fact, many cultivars require a couple of hours of direct sunlight daily if they are to look their best. The best exposure for hostas is one with morning sun and afternoon shade. Noontime and early afternoon shade is particularly important where sun is intense.
For best growth, provide a nutrient-rich, organic soil that is moisture-retentive but well drained. Hostas should receive an inch of water a week, either from natural precipitation or irrigation, throughout the growing season.
Hostas are subject to a number of fungal and viral diseases; be sure to start with healthy, disease-free plants from a reliable grower. Notched leaf margins are a sign of black vine weevils. Yellowing of the leaves in June followed by chocolate-brown streaks or blotches between the veins are symptoms of foliar nematodes, and plants infested with them are best removed and disposed of off-site. Mice and voles sometimes attack the roots and crowns; slugs, snails, and deer relish hosta foliage. Cultivars with thick-textured, waxy, blue foliage appear less palatable to deer.
With their expansive foliage, hostas furnish a uniquely luxuriant effect to partially shaded beds and borders, presenting a visually soothing contrast to such brightly colored, shade-tolerant annuals as impatiens, coleus, and wax begonias. They provide an attractive edging for shade-tolerant shrubs such as azaleas, viburnums, and hollies, and under a deciduous canopy make an outstanding follow-up for snowdrops, crocus, tulips, daffodils, and other spring-blooming bulbs. Hostas mingle easily in woodland gardens, where their bold foliage provides attractive contrast to finer-leaved neighbors including ferns, hellebores, lungworts, wild gingers, and trilliums.
Propagate named cultivars by division, ideally in late summer about 30 days before the first fall frost. Hosta seed germinates readily, though the offspring of cultivars may not possess the desirable traits of their parents. Sow outdoors in fall or stratify seed in the refrigerator and start indoors in early spring.
Hosta ‘Francis Williams’ and others play off well aginst ferns in this shade garden
Hosta crispula
• lavender
• early summer
• 1–1.5 ft. × 2.5 ft.
• part shade
• Z3–9
Curled-leaf hosta. Native to Japan. Traditionally treated as a species, but recent research has revealed it to be a form of Hosta sieboldiana. Forms cushions of long-stemmed, dull green, 5- to 7-in., ovate leaves with irregular, white margins. Racemes of 1.75-in., pale lavender flowers borne on 3-ft. scapes; as many as 40 flowers per raceme. Sensitive to hot sun; mass in shade as ground cover.
Hosta fortunei
• lilac
• summer
• 1–1.5 ft. × 2 ft.
• part shade, shade
• Z3–9
Fortune’s hosta. Japan. Treated as a species by horticulturists, but recently revealed as a form of Hosta sieboldiana. Somewhat waxy, gray-green, ovate leaves, 6–12 in. long, borne in 2-ft. mounds. Racemes of pale lilac, 1- to 1.5-in. flowers carried on 3- to 4-ft. scapes. Genetically variable, and a parent to many selections including:
‘Albopicta’ (‘Golden Spring’). Young leaves pale yellow with irregular, dark green margins; leaves become all green as they mature in summer.
var. hyacinthina (syn. H. fortunei ‘Hyacinthina’, H. ‘Hyacinthina’). Blue-gray, greenish leaves with thin, gray rim.
‘Francee’ has dark green, heart-shaped leaves rimmed with a white band. Sun tolerant; a perennial favorite.
Hosta gracillima
• purple
• late summer
• 12 in. × 30 in.
• part shade
• Z3–8
Small rock hosta (“Hime Iwa Giboshi”). Native to mountain valleys in Japan’s Kochi Prefecture. Narrow, glossy green leaves, 4 in. long and 2 in. wide, with wavy margins. Fast growing, a gem for troughs, rock gardens, or the fronts of borders.
Hosta lancifolia
syn. H. japonica
• lilac
• late summer
• 1 ft. × 1.5 ft.
• part shade, shade
• Z3–9
Narrow-leaved plantain lily. Japan. Another traditional “species” in horticulture that is probably more correctly treated as a cultivar of garden origin. Forms a mound of long-stemmed, glossy deep green, lanceolate leaves 2–6 in. long. Scapes, 2 ft. tall and spotted purple at the base, bear racemes of 1.5- to 2-in., flaring, pale flowers flushed with purple. Good for edging.
Hosta plantaginea
• white
• mid- to late summer
• 12–18 in. × 18–24 in.
• part shade, shade
• Z3–9
August lily. Native to China and Japan. Erect and spreading, this medium-sized hosta has glossy, rounded, heart-shaped, light yellow-green leaves and large, 3- to 6-in.-long, trumpet-shaped, white, heavily fragrant flowers borne on scapes up to 30 in. The common name refers to this species’ late blooming season. Attracts hummingbirds. The best species for sultry climates; thrives as far south as Jacksonville, Florida.
var. japonica (var. grandiflora, ‘Grandiflora’) is exceptionally vigorous, to 26 in. tall and 46 in. wide.
‘Royal Standard’ is a cultivar of long standing with very fragrant white flowers. Tolerates full sun as long as it is not intense. Carefree and reliable.
Hosta sieboldiana
• white
• early summer
• 2–3 ft. × 3–4 ft.
• part shade, shade
• Z4–8
Siebold’s hosta. The species is native to Japan, and is usually available in the nursery trade in the form of the cultivar Hosta sieboldiana ‘Elegans’ (sometimes listed as var. elegans; more correctly var. sieboldiana). Thick textured and corrugated, the large 13 in. × 10 in., blue-green leaves are heart shaped; funnel-shaped flowers, 1–1.5 in. long, are white with a violet tinge, and borne on 36-in. scapes. An exceptionally shade-tolerant hosta, but slow growing. The blue color is due to a wax on the leaf surface that rapidly degenerates in hot climates.
‘Frances Williams’ has large, rounded and cupped, bluish green leaves irregularly bordered with gold. White flowers.
Hosta sieboldii
syn. H. albomarginata, H. lancifolia var. marginata
• lilac
• late summer
• 1 ft. high and wide
• part shade, shade
• Z3–9
Seersucker’s hosta. Native of Japan with undulate, lanceolate, dark green, 4- to 5-in. leaves, matte above and shiny beneath. Racemes of nodding, bell-shaped, 1.5- to 2-in., white flowers veined with purple.
‘Kabitan’ has pale yellow-green leaves with green margins and violet flowers.
Hosta undulata
syn. H. lancifolia var. undulata, H. media-picta, H. variegata
• lilac
• early summer
• 1.5 ft. × 1–1.5 ft.
• part shade, shade
• Z3–9
Wavy-leaf plantain lily. Of horticultural origin. Wavy, sometimes contorted leaves with elliptic to ovate, green blades 5–6 in. long, marked with a broad cream central stripe and edged with darker green.
‘Albo-marginata’ (‘Silver Rain’) has tapering, elliptic leaves, gray-green at the center, margins rimmed with cream. Fast growing, spreads, a handsome groundcover.
‘Variegata’ (‘Undulata’), to 10 in., has smallish leaves irregularly streaked with white at the center and undulating green margins, twisted leaf tips.
Hosta ventricosa
• purple
• summer
• 4 in. × 12 in.
• part shade, shade
• Z3–9
Dark purple–flowered hosta (“Murasaki Giboshi”). Native to China and Korea. A natural dwarf with heart-shaped, glossy dark green leaves with twisted tips and vivid blue-purple flowers.
Hosta venusta
• violet
• early summer
• 4 in. × 1 ft.
• shade, part shade
• Z3–9
China, Korea. Diminutive, 1- to 2-in. leaves with long petioles; 10- to 12-in. scapes bear sparse racemes of 1–1.5 in., funnel-shaped flowers that are violet marked with darker veins.
‘Variegated’ has leaves with cream centers and wavy margins in various shades of green.
Other Notable Cultivars
Because hostas hybridize readily, professional and amateur breeders have created a dizzying number of cultivars—some 6000 were in commerce at last count. Within this plethora, there is considerable variation in adaptation to climate and conditions.
For starters, leaf color can provide a clue as to light requirements. In general, hostas with yellow or golden leaves (like ‘Gold Regal’) can stand more sun than hostas with green, blue, or white-variegated leaves. Unless they receive at least a couple of hours of full sun daily, preferably in the morning or after midafternoon, the yellow-leaved hostas take on an unattractive greenish tint. Blue-leaved hostas such as ‘Blue Mouse Ears’ may tolerate such sunnier sites in cooler, northern climates, but their blue color is likely to fade to green unless protected from direct afternoon sun, especially where it is very strong. White-variegated hostas also tend to prefer shadier sites, though cultivars with thicker leaves (e.g., ‘Francee’) are more sun tolerant. Bleached patches on the leaves that turn brown and then fall away usually indicates sunburn.
Hosta ‘Blue Mouse Ears’ benefits from afternoon shade
In terms of climatic adaptation, as a rule, hostas that bear fragrant flowers, like the species Hosta plantaginea and its hybrid descendants such as ‘Fragrant Bouquet’, ‘Fragrant Dream’, and ‘Summer Fragrance’, are the most tolerant of heat and humidity. Typically, fragrant-flowered hostas also share golden-leaved hostas’ requirement for extra sunlight, and seem to be extra attractive to deer.
Visit the American Hosta Society’s directory (www.americanhostasociety.org/DisplayGardens.html) of outstanding hosta display gardens for regionally oriented cultural information, and selections appropriate for your region.
Saururaceae
chameleon plant
This relative of lizard’s tail (Saururus) is just as invasive and the site on which it is planted must be carefully selected if it is not to become a nuisance. In the right location, however, chameleon plant makes a fine dense groundcover, spreading by fast-growing rhizomes that are almost impossible to eradicate.
Plant in moist, humus-rich soil, in sun or shade. Damp soil causes the plant to spread more rapidly, but dry conditions curtail invasive tendencies. It grows well in 3–4 in. of water at a pond side, but not in deeper water. Where spread must be controlled, confine to containers. Mulch deeply through the winter in cold regions. Propagate by dividing the rhizomes in spring, or start plants from seed.
Houttuynia cordata
• white
• summer
• 6–24 in. × 1.5 ft.
• sun, part shade
• Z5–11
Chameleon plant, lizard tail, fishwort. Moist, shaded woodlands and scrubland, Japan, Korea, and southeast Asia. Trailing stems root at the nodes, while the stem tips are erect. Leaves are matte bluish green, tinted with red along the rims, and about 1–3.5 in. long. They are broadly heart shaped, borne alternately on the stem. Terminal, 1-in. spikes of yellow-green flowers are decorated with four to six showy petal-like, white bracts at the base.
‘Chameleon’ (‘Tricolor’, ‘Court Jester’, Variegata’) has brightly variegated leaves edged with cream and speckled with red. These may revert to all green especially in warm climates, and have less defined variegation in more shade.
‘Flore Pleno’ (‘Plena’) has eight or more clean white bracts producing a “double” effect. Just as aggressive as the species.
Houttuynia cordata
Papaveraceae
Mexican tulip poppy
This genus consists of a single species, Hunnemania fumariifolia, popular for its sunny yellow poppy flowers and cut blue-green foliage. One explanation of the specific epithet is that it alludes to the smoky gray color of the fine-textured leaves—fumus meaning “smoke” in Latin. California poppy (Eschscholtzia californica) is a relative of Hunnemania, and there is an obvious resemblance in the flowers.
Tulip poppies thrive in full sun in average, well-drained soil. Once established, they tolerate droughty conditions; suitable for xeriscapes. Plant on a slope to enhance the runoff of excess water; be mindful not to overirrigate. The showy yellow flowers bloom for several months and do especially well in dry California gardens.
Propagate from seed sown in fall or early spring in situ, or in containers to avoid root disturbance at planting time. If grown as a winter-blooming sunroom specimen, sow in fall. Early bloom may occur in mild climates.
Hunnemania fumariifolia
• yellow
• early summer to late fall
• 2–3 ft. × 1–1.5 ft.
• sun
• Z9–11
Mexican tulip poppy, tulip poppy, Mexican smoke poppy. Mexican Highlands. Although considered a tender, short-lived perennial for warm areas, this bright yellow poppy is valuable in summer containers and for bedding in cooler zones. Each long-stemmed, 3-in. bloom has four crinkled petals surrounding a central boss of orange stamens. The deeply cut, bluish leaves are attractive and provide a fine ferny foil for the flowers. Self-sows freely.
Hunnemania fumarifolia
Papaveraceae
wood poppy
Closely related to weedy greater celandine (Chelidonium majus), as well as better-behaved members of the poppy family, wood poppy is well suited to shaded woods, rock gardens, or wild gardens. Here, this variable genus is regarded as having but a single species, although some botanists distinguish several. If happy, wood poppy may seed about generously, but that seldom seems to be the case.
These poppies thrive in humus-rich soils that remain damp, but drain well. They dislike waterlogged, clayey soils. Sun or part shade is ideal; in warmer climates shade from intense midday sun.
Wood poppies are fine companions for native trilliums, woodland phlox, Solomon’s seal, and other woodlanders, as well as ephemerals including Dutchman’s breeches, Virginia bluebells, and trout lilies.
The sap of these plants is the typical yellow of most poppies and may cause a skin eruption in sensitive individuals. Deer resistant, but slugs and snails find the young plants delectable. Propagate by seed sown directly where the plants are to grow or in pots to ease the trauma of transplanting; these plants are taprooted and resent disturbance.
Hylomecon japonica
syn. H. vernalis, Chelidonium japonicum, C. vernale
• yellow
• late spring to early summer
• 6–12 in. × 9 in.
• sun, part shade
• Z6–9
Wood poppy, forest poppy, Japanese poppy. Far East, Manchuria to Japan. A rhizomatous perennial, wood poppy develops low clumps of odd-pinnate leaves, with usually five light green, dentate leaflets. The beautiful, clear yellow, 2-in. flowers are four petaled, carried singly or in pairs in the upper leaf axils. The flowers are short lived and bloom time is brief. This species becomes summer dormant; foliage reemerges the following midspring.
Hylomecon japonica
Hypericaceae
St. John’s wort
Homeopathic healers prescribe St. John’s wort for various ailments, especially for mild depression. What they administer is an extract of common St. John’s wort (Hypericum perforatum), which can also lift spirits in the garden. A few other species of this large genus are also garden worthy. Many are shrubby or partly shrubby (subshrubby) and mix well in shrub collections. Notable among these are H. frondosum and its cultivar ‘Sunburst’, H. prolificum ‘Hidcote’, H. ×imodorum and its cultivars, and H. ×moserianum ‘Tricolor’. St. John’s wort flowers, which range in size from tiny to up to 3 in. across, usually have five yellow petals and conspicuously bushy central clusters of stamens. Leaves are mostly opposite or in whorls on the stems, and may be dotted with black glands.
Hypericum prolificum ‘Hidcote’
Provide a soil enriched with compost, rotted leaves, or bagged animal manure that retains moisture but is well drained; poorly drained soils promote root rot. Most species prefer a partly shaded position; some tolerate deeper shade, but in such circumstances blooming may be compromised. Deer resistant.
Propagate by seed in containers in fall. Softwood cuttings root readily in late spring, or perennials may be divided in spring or fall. Increase shrubby species by semi-ripe cuttings taken in summer.
Hypericum androsaemum
• yellow
• midsummer
• 24–30 in. × 36 in.
• sun, part shade, shade
• Z5–8, HS
Tutsan. Western Europe, Mediterranean basin to northern Iran. A bushy, deciduous subshrub that blooms on new growth and can be cut back hard to develop a framework of branches in early spring. Tolerates drought well. The 3- to 4-in.-long leaves are sessile and entire, without black glands. Bright yellow, cup-shaped flowers may reach a diameter of 1 in., and gather in cymes of three to nine blooms. Colorful, decorative, yellow fruits follow, maturing to dark red and then deep brown; these are prized by florists. Mulch in winter in cold regions; although the top growth may be killed back, the roots usually send up new shoots in spring. Self-seeds; it has become invasive in Australia and New Zealand. Susceptible to wilt and root rot in hot, humid climates. Mass on the margins of woods, or informal banks and slopes; useful as a low hedge.
‘Albury Purple’ has exciting fragrant, burgundy-flushed foliage and decorative red-turning-black fruits. Interesting as a low hedge. 15–36 in. Z5–8.
‘Golden Tutsan’ has golden leaves. 2–3 ft. Z6–9.
Hypericum buckleyi
• yellow
• summer
• 9–12 in. × 24 in.
• sun, part shade
• Z5–8
Blue Ridge St. John’s wort. Mountains of North Carolina to Georgia. Low growing with blunt, grayish leaves to 0.75 in. that turn reddish as temperatures cool. Excellent native groundcover.
Appalachian Sun is a seed strain. It has small, green leaves and 1- to 1.5-in., yellow flowers. Well-drained, moist, acid soil is best. 10 in. × 18 in.
Hypericum calycinum
• yellow
• summer
• 15–18 in. × 24 in.
• sun, part shade, shade
• Z5–8
Aaron’s beard, rose of Sharon. Southeast Europe, Turkey. Excellent as an evergreen or semi-evergreen groundcover, this low, shrubby plant spreads by runners. The slightly bluish green leaves, to 4 in. long, are netted with fine veins beneath. Solitary, saucer-shaped, bright yellow flowers to 3 in. across are accented with a central boss of countless stamens. Difficult to eradicate once established. Cut back hard annually in spring or every two to three years to encourage fresh young growth. Keep irrigated in summer to avoid leaf burn. Mulch in winter in cold regions.
‘Brigadoon’ has striking oval, bright gold leaves, sometimes reddish when young. Protect from burning by intense sun in warmer zones. Z5–7.
Hypericum cerastoides
syn. H. rhodoppeum
• yellow
• late spring to early summer
• 3–9 in. × 15–18 in.
• sun
• Z6–10
Gray-leaf St. John’s wort, trailing St. John’s wort. Southern Europe. Ground-hugging mats of tiny, 1.25-in., silvery leaves make this beauty a charming, weed-suppressing groundcover. Deep yellow, starry flowers cover the plants from late spring on. Keep soil damp during hot weather.
‘Silvana’ has especially silvery foliage. Lovely in rock gardens. Z6–9.
Hypericum cerastoides ‘Silvana’
Hypericum olympicum
• yellow
• summer
• 10 in. × 24 in.
• sun, part shade
• Z6–8
Olympic St. John’s wort. Greece, Turkey. Upright and deciduous with pointed, grayish green leaves, 1.5 in. long, glaucous beneath, carried on branching, trailing stems. Golden, starry flowers bloom alone or two to three together at the ends of the stems. Lovely at the front of the border or in rock gardens, where it is well mannered. Requires very well-drained soil. Start from seed or cuttings in fall.
‘Citrinum’ (syn. Hypericum olympicum subsp. uniflorum ‘Citrinum’) has small, rounded leaves, waxy white beneath, and pale lemon, starry flowers, about 2.5 in. across. Excellent for well-drained rock gardens. 15 in. Z5–8.
Acanthaceae
polka-dot plant
Best known as houseplants, polka-dot plants are tender evergreen perennials native to southern Africa, southeast Asia, and Madagascar. The most popular species is common polka-dot plant, Hypoestes phyllostachya. Where winters are mild it is planted extensively among shrubs, and in beds and borders; in chillier regions it is valued as a summer foliage plant. Common polka-dot plant is also effective in containers, window boxes, and baskets. These, of course, can be brought indoors to decorate sunrooms and conservatories through the cold months. Extensive hybridization has developed many intricately variegated leaf types.
Slightly shrubby at the base, this mounding or sprawling plant has opposite, 3-in.-long leaves that are usually ovate, often with a velvety surface. Tubular, two-lipped flowers cluster into dense racemes or are held singly at stem tips and in leaf axils. Humus-rich, well-drained soil is ideal; do not allow plants to dry out in hot weather. Although plants usually recover from a spell of drought, they often lose lower leaves as a result. Maintain a bushy habit by pinching young plants in spring, and then again sporadically through the season.
White fly and powdery mildew may need control, especially indoors; slugs may attack tender young growth, but deer seldom browse. Propagate from stem cuttings in spring or summer, or sow seed in spring.
Hypoestes phyllostachya
syn. H. sanguinolenta of gardens
• lavender
• late summer to fall
• 12–30 in. × 9–24 in.
• sun, part shade
• Z9–11
Polka-dot plant, freckle face, measles plant. Madagascar. Dark green leaves irregularly spotted with pink freckles or blotches; selections and cultivars are chosen for more involved leaf patterning. Tight racemes of tiny, lavender flowers bloom in the latter part of the growing season, but are visually insignificant and are often removed by gardeners.
‘Carmina’ has bright red leaves.
Confetti Seed Strain includes cultivars with carmine, pink, red, wine-red, and white foliages. Recommended for containers and baskets.
‘Purpuriana’ has plum-colored leaves.
Splash Select Series is another seed strain producing plants with foliage in individual colors: pink, red, rose, or white. 6 in.
‘Wit’ has dark green leaves marbled with white.
Hypoestes phyllostacha ‘Confetti Carmine Rose’ provides a color echo for Primula malacoides ‘Prima’
Lamiaceae
hyssop
Traditionally used as an aromatic herb, hyssop is known for its antiseptic qualities and as an expectorant and cough reliever. When ingested in high concentrations it can be harmful. Often grown by beekeepers; hyssop is an excellent honey plant.
Plant in a sunny position in herb and medicinal gardens, as well as in bee and butterfly gardens. Suitable for low hedges, edgings, rock gardens, containers, and borders.
Hyssop thrives in full sun on fertile, well-drained soils, preferably with a high pH. Poor dry or sandy soils are also acceptable; winter wet can be lethal. Tolerates part shade, but this reduces the fragrance of the leaves. Harvest when the flowers have opened; chop and dry the crop for herbal use and for potpourri. Prune to shape and encourage bushiness in early spring, and after harvest for neatness.
Pests and diseases are seldom a problem; deer usually ignore the plants due to their aroma. Increase from seed sown in early spring, or root cuttings of soft young growth in spring. Plants may also be divided then.
Hyssopus officinalis
syn. H. aristata, H. vulgaris
• purple-blue
• midsummer to early fall
• 18–24 in. × 36 in.
• sun, part shade
• Z4–9
Hyssop. Central and southern Europe; it has become naturalized on roadsides and wasteland in some parts of the United States. This strongly aromatic, semi-evergreen herb has pairs of shiny, lance-shaped to linear leaves to 2 in. long and toothed along the edge; carried on branching, square stems that are woody at the base. Whorls of fragrant, two-lipped, tubular flowers arranged in relaxed terminal spikes; flowers, with prominently protruding stamens, are 0.5 in. across and usually purplish blue, occasionally pink or white. Chartreuse liqueur is flavored with hyssop oil.
Hyssopus officinalis
Brassicaceae
candytuft
Candytufts were fixtures in cottage and rock gardens of yesteryear, and endow even the most modern garden with a touch of nostalgic charm. The genus includes about 39 annual and perennial species; several of the latter are subshrubby. The name Iberis commemorates the fact that many candytufts hail from the Iberian Peninsula.
As the common name suggests, these plants grow in the form of tufts of dark green, alternate, linear, and entire leaves. Numerous flowers cluster into flattened corymbs or racemes above the foliage mass, sometimes hiding the leaves entirely. Each small flower is four petaled, with one pair of petals larger than the others. Seedpods are not decorative.
Plant in full sun or light shade in well-drained soil. Tolerates occasional drought. Shear plants after bloom by a third for neatness, and to prevent legginess. Every couple of years cut back the plants severely into old wood to rejuvenate them. Plants may be short lived in less than ideal conditions. Protect in cold-winter regions with evergreen boughs to mitigate winter burn from icy winds and sun.
Excellent in rock gardens, tumbling over rocks and walls, or between pavers and along pathways. Iberis can even be grown as an attractive low hedge, clipped to shape after bloom time. Choose compact selections for containers, window boxes, and planter boxes. Good companions include rock cress, pinks, basket-of-gold, and London pride saxifrage along with small, spring-blooming bulbs. Attracts butterflies; resists deer.
Propagate cultivars from cuttings; start species from seed.
Iberis saxatilis
• white
• spring
• 3–6 in. × 6 in.
• sun, part shade
• Z3–9
Rock candytuft. Native to rocky areas of southern Europe. Tight, low, almost prostrate cushions of evergreen, needle-like, 0.75-in.-long leaves become covered with flattened, 1.5-in. clusters of fragrant, white flowers that fade to lilac, held at the stem tips.
‘Pygmaea’ is very compact. 4 in.
Iberis sempervirens
• white, purple
• early spring to late spring
• 9–12 in. × 18 in.
• sun
• Z3–8
Perennial candytuft. Southern Europe. Mounds of evergreen, needle-like, 1.5-in. leaves; flat, 2-in.-wide clusters of flowers borne in the leaf axils.
‘Alexander’s White’ has dense clusters of chalk-white flowers. 8 in. Z4.
Iberis sempervirens ‘Alexander’s White’
‘Autumn Snow’ produces white flowers in spring; repeats in fall. Keep moist during hot weather. Possibly a better repeat-bloomer than ‘October Glory’. 8–10 in.
‘Little Gem’ has pure white flowers. Very compact. 6–12 in.
‘Masterpiece’ is a recent introduction with heads of white flowers, lilac-tinged buds. Mounding. 10 in. Z6.
‘Snowball’ makes mounds of white flowers; early. 10 in.
Balsaminaceae
balsam, busy lizzie
In recent years, market surveys have consistently found impatiens to be “America’s #1 annual.” In fact, most members of this species are perennial in their native habitats; they are grown as annuals in most of North America because they don’t tolerate frost. There is however, one species (Impatiens balfourii) that offers the vigorous growth, shade tolerance, and floriferous habit typical of the genus and is winter hardy well into our colder states. This species is also resistant to the new strain of downy mildew, which has devastated I. walleriana types sold by the millions for annual plantings. Unfortunately, it shares the genus’ susceptibility to aphids, scale, mealybugs, and slugs. Treating infested plants with insecticidal soaps is not recommended as these may be toxic to impatiens.
Mass I. balfourii in shady beds and borders, or group informally in woodland gardens. Valuable also in large tubs and planters.
Propagation by seed is easy. Stem cuttings root readily.
Impatiens balfourii
• lavender, pink, white
• early summer to early fall
• 2–3 ft. × 2 ft.
• part shade, shade
• Z5–11
Kashmir balsam, poor man’s orchid. Native to the lower altitudes of the Himalayas, this species prefers cool, moist climates. Stems are succulent and brittle, glabrous, reddish, and much branched, forming rounded mounds; the 1.5-in., alternate leaves are lanceolate, toothed along the margins. Orchid-like, spurred, 0.75-in. flowers have a white, crest-like sepal set above a lower lip of two pendulous, yellow-freckled, pink or lavender petals. An old-fashioned favorite that seems to be deer resistant; self-seeds prolifically, becoming invasive in northern Europe. Ideal for cottage gardens.
Bignoniaceae
hardy gloxinia
Although the flowers of these plants resemble those of gloxinias in the African violet family, they are actually relatives of trumpet vine (Campsis radicans); formerly, some of the species were listed as Amphicome. Hardy gloxinia roots are tuberous, fleshy, and easily damaged. New growth emerges very late in spring, so mark these plants to avoid accidentally disturbing them.
The two-lipped flowers are trumpet shaped, flaring at the mouth, and carried on strong upright stems above a rosette of pinnately divided leaves. Plant the crowns 3–4 in. deep in well-drained, average to rich soil, in sun, or part shade where sun is intense. They resent winter wet that may cause root rot. Protect with mulch in cold-winter zones.
Propagate by division in spring, being careful to break the roots as little as possible. Young basal shoots may also be rooted then. Growth from seed is slow; protect young seedlings indoors over their first winter.
Incarvillea arguta
syn. Amphicome arguta
• pink
• early to midsummer
• 24–36 in. × 12 in.
• sun
• Z7–9
Himalayan gloxinia. Native to rocky limestone regions of the Western Himalayas to western China. Elegantly bushy with upright, branching, reddish stems, woody below, clothed with finely cut, fern-like, pinnate leaves, to 8 in. long. These are arranged alternately on arching stems and carry two to six pairs of opposite, lance-shaped, coarsely toothed leaflets. Racemes of nodding, penstemon-like flowers, 1.5 in. long, are long blooming. Deadhead to prolong bloom time. In cold regions grow as an annual, or in a container overwintered with protection. Elegant at the feet of climbing clematis or other vines.
Incarvillea delavayi
• pink
• late spring to midsummer
• 1–2 ft. × 15 in.
• sun
• Z5–10
Hardy gloxinia, Chinese trumpet. Native to China’s Yunnan Province. Basal rosettes of deeply divided, dark green leaves to 12 in. long, composed of up to 11 pairs of toothed, oblong leaflets. Clusters of six or more flared trumpet flowers, yellow at the throat, and ruffled along the rim. Excellent for containers or at the front of perennial or mixed beds and borders.
‘Bee’s Pink’ has soft pink, extra-large flowers, yellow at the throat.
‘Snowtop’ (‘Alba’) has pure white flowers.
Incarvillea mairei
• deep rose
• late spring to early summer
• 1–1.5 ft. × 6–8 in.
• sun
• Z5–9
Garden gloxinia, dwarf hardy gloxinia. Himalayas to western Nepal, southwest China. A forgiving plant tolerant of most soils with pH ranging from 5.5 to 7.5. Erect, clump-forming garden gloxinias have basal rosettes of bright green, pinnate foliage. Short, leafless stems bear several very large, deep rose to magenta trumpet flowers, with yellow throats and white flaring. Valuable in rock gardens, perennial and mixed beds and borders, and in containers. Best from seed; seedlings take several years to reach bloom size.
var. grandiflora bears nodding, 3- to 4-in., crimson-pink flowers on 6-in. stems. 20 in. Z4–8.
Asteraceae
inula
If you’ve seen one yellow daisy, have you seen them all? Not really. Leopard’s bane, arnica, and inula are superficially similar flowers, but each has its own charm, strengths, and weaknesses. Inulas offer bold, if sometimes coarse, rough foliage, typically with large basal leaves, the upper ones diminishing in size. Flowerheads are solitary or grouped, flattish, with slender, yellow ray flowers surrounding darker-colored, tubular disk flowers.
Provide a sunny site with average, well-drained soil that remains moist during dry spells. Outstandingly cold hardy, inulas commonly do not tolerate the heat and humidity of southeastern summers. The low-growing species are appropriate for rock gardens and the edges of beds and borders; mass larger species between shrubs to dramatic effect. Deadhead for a long bloom season.
Propagate by seed or division in spring
Inula ensifolia
• yellow
• late spring to early summer
• 1–2 ft. × 1 ft.
• sun
• Z3–7, HS
Swordleaf inula, elecampane, horseheal. Caucasus region of Europe. This easy, compact perennial branches freely, and is topped with solitary or groups of slender-rayed, 1- to 2-in., orange-yellow daisies. Coarse, willow-like leaves are sessile, alternate, and parallel veined, hence “ensifolia,” which means “leaves like swords.” Their bloom time may last six weeks or so; excellent cut flowers. Prone to powdery mildew.
‘Compacta’ grows to only 6 in.; charming in rock gardens.
‘Sunray’ produces its golden-yellow daisies in summer. 1.5 ft. Z3–9.
Inula helenium
• yellow
• midsummer
• 2–6 ft. × 3 ft.
• sun, part shade
• Z3–7
Elecampane, horseheal, marchalan. Britain, Europe to western Asia; naturalized in the United States. These large and rather coarse but impressive plants have huge lower leaves, 2–3 ft. in length; stem leaves are smaller and sessile. The foliage is rough-hairy on the upper surfaces, downy-soft beneath. The 2- to 3-in.-wide flowerheads may be solitary or borne in groups. Keep soil moist. Best confined to herb gardens. Valued as a medicinal herb for centuries. Sweet candy cakes were formerly made from elecampane.
Inula royleana
syn. I. macrocephala, I. racemosa
• yellow
• late summer
• 24–30 in. × 18 in.
• sun
• Z3–7, HS
Himalayan elecampane. Western Himalayan Mountains region, especially Kashmir. Clump forming and erect, with black flower buds that open to shaggy, orange-yellow, 5-in. blooms on unbranched stems. Basal leaves are ovate, 6–10 in. long, furry beneath and with winged petioles; upper leaves are elliptic, to 8 in., with enlarged, stem-clasping bases. Excellent cut flower. This plant has a long history of medicinal use; the roots have been used to make an expectorant, among other things.
Iridaceae
iris
Notable for its myriad of floral colors, iris is appropriately named for Iris, Greek Goddess of the Rainbow. This huge genus of about 300 species is native throughout northern temperate regions of the world, where it grows in chilly mountain areas as well as in meadows, on hillsides, and beside streams in North America, Europe, Africa, and Asia. Various forms have been cultivated for centuries and many are depicted in art (think Vincent van Gogh and George Gessart) and in emblems, particularly the ‘Fleur de Lis’ of French kings and of Scouting, and on the flags of St. Louis, Missouri, and Quebec, Canada.
The genus is often divided according to whether the particular species grow from bulbs, rhizomes, or fleshy rhizomatous roots. Foliage is mostly sword-shaped, narrow or broader according to type, and sometimes arranged in fans. The flowers, solitary or several per stem, have floral parts in trios; three inner “standards” that are generally upright, three outer “falls” that are often reflexed; the three-branched style has stigmas on the underside and covers the anthers, an adaptation to expedite pollination by flying insects and ants, or others seeking nectar. A three-part fruiting capsule follows; sometimes these are valued for dried winter floral arrangements.
Most irises require a sunny position to thrive, although some tolerate afternoon shade; crested iris do well in woodland shade. A few types such as the Louisiana irises thrive in wet soils, but most irises prefer well-drained soils of average to good fertility. Soil pH is seldom critical, except in the case of Japanese iris, which demands lime-free soil. Note that Iris pseudacorous, native to Europe, western Asia, and northwest Africa, though often found in nurseries, has proven invasive, although its cultivars behave better.
There is an iris for almost every spot in the garden. Tall species mix well with shrubs and other tall perennials toward the back of borders, while the slightly lower-growing bearded, Siberian, and Japanese types are colorful midborder plants, contrasting well with more rounded spurges, bleeding hearts, ornamental sages, and peonies. Bulbous netted and Danford iris are suitable for rock gardens and small spots where color is needed. They force well for early indoor displays. Bulbous Dutch iris are popular cut flowers. Japanese roof iris, I. tectorum, and winter iris, I. unguicularis, deserve mention for iris fanciers.
Deer seldom browse iris, though they occasionally nip off the blossoms of crested types, generally leaving behind the decapitated blossoms. Other pests include iris borers on rhizomatous types and thrips that attack the flowers. Both can become seriously destructive if not controlled.
Propagate by division. Start species from seed, though seedlings take a couple of years to reach blooming size. Check out specialist nurseries for the most recent introductions.
Iris cristata
• blue, purple
• spring
• 3–9 in. × 15 in.
• part shade, shade
• Z3–8
Crested iris, dwarf crested iris. Native to woodlands of the eastern United States, from Maryland to Oklahoma and Georgia. Slender, creeping, woody rhizomes spread widely along the surface, and function effectively as groundcovers. Fans of narrow, sword-shaped, 4- to 8-in.-long leaves; fragrant, almost stalkless flowers 1–1.5 in. across are held on 1.5- to 2-in. perianth tubes. Flowers may be solitary or paired, have upright monochrome standards, spreading falls decorated with a cream or yellow crest, and a large central white blotch or signal usually rimmed with purple or violet. Be alert for slugs that shred the foliage and damage the blooms too. Spectacular when allowed to naturalize in light woods or clearings, or on shaded rocky slopes and in rock gardens.
‘Eco Bluebird’, one of several cultivars introduced by Eco-Gardens, has dark blue flowers crested with orange and a white throat.
‘Powder Blue Giant’ has large, open flowers of pale lavender; purple-rimmed white blotches.
‘Shenandoah Sky’ has deep lilac flowers, yellow crest, and purple-rimmed white blotches on the falls.
‘Tennessee White’, selected by Don Shadow, is vigorous with white flowers decorated with a yellow crest. Possibly the best white.
‘Vein Mountain’, introduced by We-Du Nursery, has very light blue flowers, with orange crests outlined with deep purple.
Iris ensata
syn. I. kaempferi
• various
• summer
• 2–3 ft. × 1.5–2 ft.
• sun
• Z4–9
Japanese iris, Japanese water iris. Native to Japan, China, Korea, India, and eastern Russia. Grassy leaves to 2 ft. long, each with a conspicuous raised midrib, emerge from stout rhizomes. From two to four flowers, usually 4–6 in. across, in white, blues, purples, and reddish violet are borne on sparsely branching stems; some modern cultivars may have flowers to 10 in. across. Blooms appear flat with arching falls blotched with yellow, and slightly smaller, almost flat standards. Requires an acid, humus-rich soil, moist but not necessarily boggy. Never apply lime. Plant about 2 in. deep as soon as possible without the roots drying out. Divide in fall or just after bloom time.
Superb for rain gardens, beside water gardens, and in shallow ponds. However, Japanese irises also thrive in ordinary garden soils, and provide magnificent displays among astilbes and hostas.
There are countless cultivars; the following is a small selection:
‘Dragon Tapestry’ is white-splashed, dark burgundy.
‘Eleanor Perry’ has deep lilac flowers traced with violet.
‘Great White Heron’ is semi-double and pure white.
‘Lion King’ has frilly, purple-edged white falls flashed with yellow.
Iris ensata ‘Lion King’
‘Pink Frost’ is lightly ruffled with lavender-pink flowers, yellow at the center.
Iris foetidissima
• mauve
• spring to summer
• 1.5–2.5 ft. × 1.5–2 ft.
• sun, shade
• Z6–10
Stinking iris, Gladwyn iris, foetid iris. Britain, southern and western Europe, northern Africa. This unusual iris is grown predominantly for its colorful seeds. Evergreen, 2- to 4-ft.-long, sword-like leaves have a very slight, unpleasant odor when bruised. Growing from slow-spreading rhizomes, the two- to three-times-branching flower stalks, flattened on one side and shorter than the leaves, each bear up to three, pale grayish, 2.5-in. flowers with bronzy yellow falls. Blossoms open consecutively, but many-stemmed plants may flaunt a dozen simultaneously. Seedpods similar to Brazil nuts follow; these split into three sections, each revealing two rows of round, scarlet, sometimes yellow or white (‘Fructo-alba’) seeds. Sow fresh seed when possible; slow to establish. Remove shabby leaves after winter. Use seedpods for dried arrangements. Tolerates coastal gardens, and almost pure sand, as well as tree roots in shaded spots.
‘Citrina’ has pale yellow flowers veined in purple. A superior cultivar.
‘Holden Clough’ (probably Iris foetidissima × I. chrysographes, or I. pseudacorus) is vigorous, with golden flowers overlaid with purple veining and yellow-blotched falls.
Iris ×germanica
• various
• early summer
• 8–36 in. × 9–24 in.
• sun
• Z3–10
Bearded hybrid iris, German iris. Of hybrid origin, probably the largest and most popular type of irises in cultivation. Named for the hairy “beard” that decorates the falls. The plants arise from thick rhizomes that lie close to the soil surface, sprouting fans of broad, sword-shaped gray-green leaves. Several flowers are borne on each stem. In addition to the bearded falls, the standards are erect, usually wide, and often frilly. Flower color varies from white through pastel pinks, blues, and yellows, to deep saturated bronzy golds, blues, and purples, with standards and beard often of contrasting hues. Some cultivars are fragrant, many repeat bloom, and most make lovely cut flowers. Spectacular additions to early summer beds and borders; low-growing cultivars are appropriate for rock gardens and the front of the border; tall ones bring grace to the back of borders and fit in well among shrubby cinquefoil, roses, weigelas, and other shrubs.
Plant in free-draining soil, with the rhizome half-buried or just at the soil surface; in very hot regions, slightly deeper. Divide every three to four years. Be alert for iris borers, which lay eggs in the rhizomes to emerge as larvae with a built-in food supply; the larvae are pinkish white with black heads. Destroy infected plants and rhizomes, which often become mushy from bacterial or fungal infections that gain entry through the borer tunnels. Traditionally the leaf fans have been cut to about 9 in. in late summer to allow sun ripening of the rhizomes.
There are innumerable cultivars; here are a few:
‘Beverly Sills’ is slightly ruffled with pale coral-pink flowers; apricot beard. May rebloom. 32–38 in. tall.
‘Champagne Elegance’ has apricot falls; very pale pink standards. Reblooms. 28–34 in.
‘Immortality’ (‘Immortelle’) has very wide, slightly ruffled, white falls; buttercup-yellow beards. Reblooms. 30–36 in.
‘Raspberry Blush’ is pale crushed-raspberry color with darker patches on the falls; orange-raspberry beards. 18–24 in.
‘Superstition’ is so deep purple as to appear almost black. 32–38 in.
Louisiana Iris
• various colors
• summer
• 3–4 ft. × 3 ft.
• sun
• Z4–9
This group of distinct species is found wild in marshes and wetlands along the Gulf Coast of Texas and Florida, and in the Mississippi basin. Species include: brick-colored Iris fulva (syn. I. cuprea), blue-flowered I. brevicaulis (syn. I. foliosa, I. lamancei), blue-violet I. giganticaerulea, purple and white-flowered I. hexagona, and reddish purple or yellow I. nelsonii. Breeding programs have produced several notable hybrids. Elegant, beardless and crestless flowers, with slender falls and floppy standards, come in an astonishing range of colors. Louisiana irises thrive in moist beds and borders, and are excellent cut flowers. Plant 2 in. deep in fall and mulch heavily. Easily divided.
Iris pallida
syn. I. glauca, I. odorissima, I. pallido-coerulea
• lavender
• late spring
• 2–4 ft. × 2 ft.
• sun
• Z4–9
Sweet iris, orris, Dalmatian iris. Northern Italy, Croatia. Long, fat rhizomes support sword-shaped, glaucous, almost evergreen leaves to 1.5 in. wide. Sparsely branched, leafless stems bear several flowers enclosed in papery silver spathes, well above the foliage. The pale lavender, yellow-bearded flowers smell deliciously of vanilla, orange blossom, or grape jelly depending upon your nose. All variants have excellent, good-looking foliage that persists through summer and contrasts with the rounded form of the plants. Fine in rock gardens, beds and borders, and fragrance and herb gardens.
‘Argenteo-variegata’ (‘Alba-variegata’) has blue-gray leaves striped longitudinally in creamy white. Powder blue flowers.
Iris pallida ‘Argenteo-variegata’
‘Variegata’ (‘Zebra’, ‘Aurea-variagata’). The glaucous leaves are striped with yellowish cream. Similar flowers and perhaps more vigorous than the white-striped selection.
var. dalmatica is a superior selection with more saturated color. Yellow beards.
Iris sibirica
• blue
• late spring
• 24–36 in. × 24 in.
• sun, part shade
• Z3–9
Siberian iris. Central Europe to southern Russia, northern Asia. Easily grown, makes dense, upright clumps of bright green, narrowly lance-shaped leaves that remain handsome through the season. Branched stems carry up to five beardless flowers, each about 3 in. across, usually well above the foliage mass. The species has blue-violet flowers with dark veining and white throats. Slow spreading but persistent. There are countless cultivars in assorted colors; a few popular ones are listed below:
‘Butter and Sugar’ has white standards, creamy-lemon falls. 3–3.5 ft. Z5–10.
‘Caesar’s Brother’, an old cultivar, is very upright with deep purple flowers. 1.5–3 ft.
‘Pink Haze’ has soft pale lavender falls, rimmed with white, dark throat. 30 in.
‘Super Ego’ has soft light blue flowers; wavy falls etched with deep blue. 32 in.
Iris sibirica ‘Super Ego’
‘White Swirl’ has white flowers, yellow at the throat. 24–30 in.
Iris tuberosa
syn. Hermodactylus tuberosa
• yellow-and-deep purple
• late winter to early spring
• 12–15 in. × 6 in.
• sun
• Z6–8
Snake’s-head iris, black iris, Herme’s fingers. Greece, Spain, Turkey. Evergreen clumps of sword-shaped, gray-green leaves, to 12–15 in. long, arranged in two ranks. Very early blooming; fragrant, 2- to 3-in. flowers with spatulate, glassy green falls, dramatically blotched with very deep purple. The erect, 1-in., pea-green standards surround a greenish yellow, conspicuously three-forked style.
syn. Laurentia, Solenopsis
Lobeliaceae
laurentia
Currently the nomenclature of this genus is somewhat confused. That said, there are a couple of species that are garden worthy, though they might be offered under synonymous names in the marketplace. Flowers are similar to related Lobelia, but they differ in having entire, not split, corollas. Mostly solitary, the flowers are blue, pink, or white. Provide sunny locations where soil drains well. Increase by cuttings, division, or seed.
Isotoma fluviatilis
syn. Laurentia fluviatilis
• blue, white
• spring
• 3 in. × 6 in.
• sun, part shade
• Z5–8
Blue star creeper, laurentia. Australia. Fast-growing, low mats of very small, rounded leaves, good for carpeting between pavers, beside woodland paths, and in rock gardens. Evergreen, where mild. Tiny, 2-in., tubular flowers bloom freely. Tolerates limited foot traffic; a star in the Stepables line of plants. Provide moist soil.
‘Blue Star Creeper’ has pale powder-blue flowers.
Isotoma fluviatilis ‘Blue Star Creeper’, typically used as a skirt for heucheras
‘White Star’ is a white-flowered form.
Campanulaceae
sheep’s bit, shepherd’s scabious
Just one species of this underappreciated genus appears in American gardens, and that one deserves far wider exposure. It is ideal for rock gardens, and also attractive in borders, lining a path, or displayed in a trough or container. Charming for posies.
Sheep’s bit prefers an acid, well-drained soil. Deadhead to prolong bloom.
Divide in spring, or sow seed in autumn; overwinter outdoors in a protected spot.
Jasione laevis
syn. Jasione perennis
• blue
• late spring to late summer
• 10–12 in. high and wide
• sun, partial shade
• Z4–9
Shepherd’s scabious. Southern Europe. Forms low tufts or mounds of gray-green, narrow and obovate, hairy leaves to 4 in. long. Wiry stems rise above bearing long-blooming, 2-in., pincushion-like heads of violet-blue flowers.
‘Blaulicht’ (‘Blue Light’) has bright blue flowers.
Asteraceae
false aster
Until recently this small genus was usually included with Aster or sometimes Boltonia, and despite the botanical divorce, members of Kalimeris much resemble their better-known relatives. Kalimeris bears its compound, aster-like flowers in late summer into fall, and over time they form extensive colonies to make a splendid show in meadows or wild gardens. False aster is sufficiently refined and attractive to use as specimens in fall borders; an excellent source of cut flowers.
Kalimeris differs from many of its aster relatives in its heat and humidity tolerance, making it reliable for planting in hot, humid climates. Generally pest and problem free; deer resistant.
Propagate by seed or divide in spring or fall; cuttings of young spring growth root readily.
syn. Calimeris incisa
• white, blue
• late summer to midfall
• 3–4 ft. high and wide
• sun, partial shade
• Z5–9, HT
Blue star aster. This native of northeastern Asia bears dark, oblong-lanceolate leaves to 3–4 in. long with toothed or incised edges, and 1-in., daisy-like, white or light blue flowers with yellow centers. Unparticular about soil as long as it drains well; prefers moderate moisture but drought resistant once established. Cut back by a third or half in early summer to stimulate vigorous, compact, and bushy growth. Protect from midday sun in the southern part of its range. Cut back after first bloom flush to encourage rebloom.
‘Blue Star’ (syn. Boltonia incisa ‘Blue Star’) is compact, with 1-in. flowerheads with light blue rays and yellow centers. Low maintenance. 12–18 in. tall.
Kalimeris incisa ‘Blue Star’
‘Edo Murasaki’ is compact with lavender flowerheads. 15 in.
Kalimeris pinnatifida
syn. Asteromoa mongolica, Kalimeris mongolica, Aster cantoniensis, Boltonia cantoniensis
• white
• early to late summer
• 2–3 ft. × 2 ft.
• sun, part shade
• Z6–9
Double Japanese aster, orphanage plant, perennial false aster. Japan. Upright and bushy arising from a basal rosette of pinnately lobed, light green leaves to 3.5 in. long. White flowerheads are semi-double, chrysanthemum-like, 1 in. across.
‘Hortensis’ is most often found in nursery catalogs. Upright, tough, and long lived, this is a real workhorse in the garden. It produces delicate clouds of semi-double, white daisies, that always seem fresh from midsummer through fall.
Kalimeris yomena
syn. Aster yomena
• white
• late summer to midfall
• 24–36 in. high and wide
• sun, part shade
• Z5–8
Japanese aster. Central and southern Japan. Serrated, oblong to elliptical leaves to 1 in. long, and white daisy-like, yellow-centered, single flowerheads.
‘Aurea’ has a slow, creeping habit. Pale lavender flowers with yellow centers and cut-leaf, gold-rimmed leaves. 12–18 in.
‘Shogun’ (syn. Kalimeris incisa ‘Shogun’, ‘Variegata’) makes dense clumps of medium green leaves broadly banded with creamy yellow. Best variegation in partial shade. Yellow-centered, light lavender flowers. 18 in. × 10 in.
Hydrangeaceae
yellow waxbells
This genus is notably compact, including just two, closely similar species; some botanists regard them as one. However you define them, yellow waxbells offer woodland plantings with a difference: unlike so many forest dwellers, these plants wait until late summer to bloom. The yellow flowers are borne in cymes at the stem tips and upper leaf axils; individual blooms are bell shaped and waxy looking, 1–2 in. long. Out of bloom, the bold and maple-like foliage, borne on arching purplish stems, catches the eye, particularly when the leaves adopt their golden fall color. Seeds are carried in interesting, three-horned, brownish green capsules.
Kirengeshomas form slowly increasing clumps. They mingle well with shrubs and provide a fine textural contrast to astilbes, ferns, and other woodlanders. In addition, yellow waxbells provide ongoing summer and fall interest in areas planted with spring ephemerals.
Best suited to moist, acid, humus-rich, well-drained soils. No serious pests or diseases, except for deer that devour them.
Divide in spring, or sow fresh seed in a protected spot outdoors.
Kirengeshoma koreana
• yellow
• late summer to early autumn
• 3 ft. high and wide
• part shade, shade
• Z5–8
Japanese yellow waxbells. Native to Korea. Often treated as a variant of the following species, Kirengeshoma palmata. Flowers of K. koreana flare outward at the mouth of the bell.
Kirengeshoma palmata
• yellow
• late summer to early autumn
• 3–4 ft. × 2–3 ft.
• part shade, shade
• Z5–8
Yellow waxbells. Native to Japan, Korea, and perhaps northeast China. Leaves are coarsely toothed, deeply lobed, and maple-like, to 8 in. across. Typically the drooping, waxy, slender, yellow bellflowers measure 1.5 in. long, and are usually borne three per cluster (or cyme).
Kirengeshoma palmata
Dipsacaceae
knautia
This genus of some 40 species has just one that is routinely planted in ornamental gardens. The flowers are reminiscent of those of related Scabiosa.
Knautia thrives in average, well-drained soil, and tolerates drought when established; if supplemental watering is required apply at the base of plants to discourage powdery mildew. Otherwise these low-maintenance plants are pest and disease free; deer seldom browse them. In flower borders, yellow or buff-colored roses make good companions, or for a more lively display, partner Knautia with Coreopsis ‘Moonbeam’ or Achillea ‘Moonshine’. Mass in cottage gardens, in meadows with grasses, and in wild and wildlife gardens. The flowers are excellent for cutting, both fresh and dried.
Propagate by seed, or take cuttings from young growth.
Knautia macedonica
syn. Scabiosa macedonica, S. rumelica
• maroon
• summer
• 1.5–3 ft. × 2 ft.
• sun
• Z5–9, HS
Macedonian knapweed. Found growing among grasses in open meadows and light woodlands in eastern and southern Europe. In average, well-drained soil Knautia makes bushy tangles of slender, hairy stems topped with bright ruby or maroon heads of flowers. These consist of a dome of fertile florets surrounded by many showier, colorful sterile ones. Individual flowerheads go to seed within a couple of weeks, but plenty are always coming so that bloom persists for many weeks. Birds, hover flies, and bees are attracted to the nectar; birds and other wildlife also feed on seeds of spent flowerheads, so do not deadhead too assiduously. Instead, periodically prune out largest spent stems to encourage rebloom without penalizing wildlife.
‘Mars Midget’ is a dwarf version, with ruby-crimson, pincushion heads. Reportedly it thrives in the very hot, humid US Gulf Coast states. 12–16 in.
‘Thunder and Lightning’ is notable for its irregularly cream-edged, light green leaves that contrast brightly with double, brilliant cherry-red flowers. A fine container plant. 12–18 in.
Knautia macedonica
Asphodelaceae
torch lily, red hot poker
These flamboyant exotics won an enthusiastic following among 19th century gardeners before the tastemakers of the day branded them as vulgar, and they fell out of fashion. Today their popularity is on the rise and once again they are sought after as dramatic players for mixed and perennial beds. Extensive breeding programs, involving Kniphofia galpinii, K. uvaria, K. praecox, and K. macownii, have produced plants with more than red-and-yellow torches; cream, lime green, yellow, and varied coral flowers are not unusual; several are named below.
This genus includes natives from temperate regions around the world, but especially from southern Africa and Madagascar. Deciduous or evergreen, especially in mild climates, torch lilies are tough and long lasting. They arise from dense mats of cord-like fibrous roots that produce tufts of grassy leaves of varying widths—some quite handsome. Strong upright scapes carry usually dense “pokers” of stemless, tubular flowers, which open from the bottom up. The pokers vary in shape with the species or selection.
Plant in spring in open, sunny or partly shaded sites, in well-drained soil high in humus. The crowns should not be deeper than 2–3 in. deep. The roots require plenty of water during bloom time; if allowed to dry out, the flower buds may abort. Winter wet causes crown rot.
Torch lilies provide colorful focal points, especially among shrubs; group together to make a statement. In beds and borders, designs benefit from the addition of these vertical plants to contrast and complement rounded coneflowers, baptisia, asters, and hydrangeas. A planting of torch lilies marching down the edge of a driveway is unforgettable. Long lasting as cut flowers. Seldom browsed by deer; a nectar source for butterflies and other insects.
Leave roots undisturbed once established, except for division in springtime to relieve overcrowding or multiply stock. New plants may be started from seed, though seedling growth is slow. Outside their hardiness zones, cultivate torch lilies in containers and overwinter indoors, or lift carefully in fall and store in a cool but frost-free location. In marginal zones, traditionally the leaves have been tied up to cover and protect the crown.
Kniphofia caulescens
• coral
• late summer
• 3–4 ft. × 2 ft.
• sun, part shade
• Z5–10
Blue-leaf red hot poker. High grassy slopes in South Africa’s Drakensberg Mountains. This dramatic plant produces tufts of fibrous, strongly blue, strappy, 36-in. leaves, wider at the base. Fat, oblong cylinders of flowers, bright coral fading to lemon, are carried on erect, short, but sturdy stems.
Kniphofia uvaria
syn. K. alooides, Tritoma uvaria
• red
• summer
• 3–5 ft. × 4 ft.
• sun
• Z5–9
Red hot poker, common torch lily, poker plant. Cape Peninsula, South Africa. Evergreen plants are variable, developing heavy clumps of sword-shaped grayish leaves about 3 ft. long. Be careful working around them as the edges of the leaves are frequently abrasive and bloody hands result. Long pokers of 1- to 2-in. flowers, red in the bud but maturing to orange or yellow, adorn stiff scapes. Largely replaced in commerce by its hybrid offspring.
‘Alcazar’ blooms early with light terra cotta flowers. 3–4 ft.
Kniphofia ‘Alcazar’
‘Earliest of All’ is among the earliest to bloom. Orange red to yellow. 2.5 ft.
‘Echo Mango’ has soft apricot flowers in late spring and summer; repeats. 3.5 ft.
‘Green Jade’ has long, icy, lime-green cylinders of flowers, paler at the tip. Midsummer. 4–5 ft.
‘Little Maid’ is excellent for containers. Long, slender spikes of creamy-white flowers. Late. A Beth Chatto introduction. 2 ft.
‘Percy’s Pride’. Very large, light yellow to lime flowers cluster tightly in oval torches. Early and repeats. Strappy, 1-in.-wide leaves. 3 ft.
Malvaceae
seashore mallow, saltmarsh mallow
This genus includes 30 or more species worldwide, but just one commonly contributes to American gardens. Virginia saltmarsh mallow is salt tolerant and an excellent choice for seaside gardens. It is also lovely at the back of the border, in native plant gardens and wildlife gardens. A favorite of hummingbirds and butterflies.
Full sun is best for good displays of flowers. While it will grow in shallow standing water, it also thrives in regular garden soils if protected from drought by regular watering.
Propagate by seed, soaked overnight. Divide in spring or increase by cuttings in summer.
Kosteletzkya virginica
syn. K. pentacarpos
• pink
• midsummer to fall
• 3–5 ft. × 4 ft.
• sun, part shade
• Z6–9
Virginia saltmarsh mallow. This native mallow grows in brackish coastal wetlands from New York south and west to the Gulf Coast of Texas. It is tall and imposing with somewhat coarse, fuzzy, light green, triangular-ovate leaves with triangular lobes at the base. Over several weeks the plants are covered with five-petaled, 1- to 3-in., pink, hibiscus-like flowers with a golden central column of stamens. These may be solitary or clustered into panicles. Flowers open in the morning, but close at the end of the day to be replaced by fresh blossoms the next day.
Lamiaceae
dead nettle
Dead nettles are among the most popular plants for ground covers for North American and Canadian gardens. Like their mint family relatives—mints, sages, and thymes—they are square stemmed with pairs of more or less evergreen leaves and two-lipped, hooded flowers. Although many of the 50 or so species of Lamium are weedy and unsuitable for ornamental gardens, those mentioned here are valuable, mannerly perennials.
In large part, this outstanding clan is grown for its foliage, borne on stoloniferous stems. Leaves are mostly kidney shaped or triangular, coarsely toothed, wrinkled, and often attractively marked with silver or white. Flowers are white, yellow, or pink-purple, some marked with darker speckles on the lower lip. The uppermost petal forms a protective hood over the pollen-bearing stamens.
Dead nettles are easily grown in average to fertile, moderately moist soils; the sprawling stems root at the nodes. They adapt to sun, part shade, or even shaded sites in cool regions, but further south require protection from midday sun. They are challenged by combined heat and humidity.
Space dead nettles closely as ground cover, to fill in quickly and smother weeds. Valuable at the front of borders, to face down low shrubs, in rock gardens; they also thrive in containers with other shade lovers such as Chinese astilbe ‘Pumila’, lungworts, and coral bells. The most showy-foliaged specimens can stand alone in interesting containers. Mostly pest and disease free, but watch for slug and snail damage. Seldom browsed by deer.
To propagate, detach rooted plantlets, or take cuttings in early summer. Some cultivars come true from seed.
Lamium galeobdolon
syn. Lamiastrum galeobdolon, Galeobdolon luteum
• yellow
• spring
• 9–8 in. × 18 in.
• part shade, shade
• Z4–8, HT
Yellow archangel, false lamium. Europe, western Asia. Often seen as a neglected groundcover, yellow archangel provides a handsome, weed-proof blanket only if plants are cut back hard before new growth appears in spring and after bloom; pinch back straggling shoots to encourage bushiness. This otherwise low-maintenance perennial tolerates dry and alkaline conditions well; can become invasive in rich soil. Round-toothed, mid-green, 2.5-in. leaves often marked with silver; mostly evergreen. Hairy, brown-spotted, bright yellow flowers cluster in whorls in the upper stem nodes. Heat tolerant. Mostly grown for foliage.
‘Herman’s Pride’ makes neat mounds of dark green, metallic leaves, flecked with silver; yellow flowers.
‘Variegatum’ (‘Florentinum’). Foliage has broad splashes of silver; yellow flowers. A fine groundcover.
Lamium maculatum
• red, pink, white
• spring to fall
• 8–12 in. × 18 in.
• sun, part shade, shade
• Z4–8
Spotted dead nettle, spotted henbit. Native to moist grasslands and light woodlands in Europe, northern Africa to Lebanon, Syria, and Turkey. Erect to sprawling stems, usually well branched at the base. Opposite, triangular or heart-shaped, toothed leaves are softly hairy, often striped or blotched with white or silver. Flowers cluster in verticillasters in the upper leaf axils; mostly pink or purplish, with darker freckles on the two lower lobes. Bloom time is extended: the first flush appears in midspring, tapers off in summer heat, but reblooms as weather cools, usually lasting until the first hard frost. Excellent planted close as an evergreen groundcover. Pinch straggling shoots to keep compact.
Other Notable Cultivars
‘Anne Greenaway’, a British selection, has small, green-and-silver leaves, irregularly edged with chartreuse. Mauve-pink flowers. Exciting planted solo in a black container.
Lamium maculatum ‘Anne Greenaway’
‘Aureum’ (‘Gold Leaf’) has bright lemon-yellow leaves, striped with white down the middle. Pink flowers. ‘Beedham’s White’ is similar but with white flowers.
‘Beacon Silver’ has green-rimmed silver leaves, red-flushed stems, and pinkish purple flowers. ‘White Nancy’ has white flowers, light green stems, and green-rimmed silver leaves. Supplies a cool clean look in shade. ‘Red Nancy’ has rosy red flowers. Intolerant of heat and humidity.
‘Pink Chablis’ blooms from spring until hard frost in fall. Silver leaves edged with dark green. Flowers in shades of pink. A superior selection from Garry Grueber.
‘Purple Dragon’. Silver leaves edged with green; large, purple flower clusters.
Aizoaceae
ice plant
This South African genus of about 180 species is native mostly to semi-arid, coastal regions, and its members, which store water in their succulent foliage, provide drought-hardy, colorful groundcovers for regions where water is limited. In the arid Southwest and southern California large swathes of land and banks along highways and other inhospitable areas are carpeted with these glistening daisies during bloom time.
Tender, succulent perennials, erect or sprawling plants carry pairs of three-angled or cylindrical, evergreen leaves, usually grayish green but possibly turning reddish in full sun. From summer through early autumn the plants are blanketed with brightly colored, daisy-like flowers. The species of Lampranthus are quite confused in the trade, and there has been considerable hybridization, natural and otherwise. Buy plants in bloom, to ensure that the flower colors are those you desire. Excellent subjects for xeric, succulent, and rock gardens, ice plants look spectacular tumbling down banks or over rocks and walls. Outside their hardiness zone, bring plants indoors over the winter, returning them to the garden when the weather warms. Rest plants by withholding water during winter; water occasionally but deeply. Fast growing, ice plants fill a large container rapidly from a branched, 4-in. cutting.
Well-drained soil is essential for these beauties; persistently moist soil promotes rot. Nutrient-poor, stony, sandy, or rocky soil serves ice plants well. Where sun is intense, midday shade is appreciated.
Ice plant stems root at the nodes along their length; may become invasive over time. Shear spent flowers after a flush of bloom. Deer resistant; may be attacked by aphids at bloomtime.
Propagate by rooting sections of the stem in spring or summer (allow cuttings to callus over before sticking), or start from seed in spring. Keep a supply of young rooted plants to replace older ones.
Lampranthus auriantiacus
• yellow, orange
• late spring to early fall
• 12–18 in. high and wide
• sun
• Z9–11
Cape Peninsula of South Africa. Usually spreading stems, rooting along their length, with grayish green, 1-in.-long, three-sided or cylindrical leaves, rough to the touch. Usually bright orange flowers, 1.5–2 in. across. Considered by some to be invasive in California.
‘Glaucus’, yellow ice plant, has vivid bright yellow blossoms. It may outshine its parent in residential gardens.
‘Sunman’ has bright golden flowers, with a wide, white central ring.
syn. Mesembryanthemum spectabile
• pink
• early summer to early fall
• 10–12 in. × 12–18 in.
• sun
• Z8–10
Trailing ice plant. Cape region of South Africa. This very variable trailing plant has succulent, red-tipped, gray-green, triangular leaves 2–3 in. long, crowded on short branches. Flowers are pink, red, rose, or purple, 2–3 in. across.
Lampranthus spectabilis
Papaveraceae
bleeding heart
A genus of one species that was, until recently, classified with Dicentra; it is still listed mostly under its former name in nursery catalogs. Deer and rabbit resistant; mostly pest and disease free, except for aphids.
Propagated by root cuttings in winter; divide in spring or fall.
Lamprocapnos spectabilis
syn. Dicentra spectabilis
• pink, white
• mid- to late spring
• 24–48 in. × 18 in.
• part shade, shade
• Z3–8
Old-fashioned bleeding heart. Japan, Korea, Siberia. Clump forming. Similar to the dicentras but soft green, lobed foliage is less deeply and intricately cut. Tall, arching stems laden on one side with pendent, broadly heart-shaped, 1-in. flowers with reflexed outer rose-pink petals, and exserted inner white petals. Spectacular foliage and floral display in midspring; unfortunately usually becomes summer dormant, after an untidy interlude with scruffy yellow foliage. Excellent for cut flowers, often forced commercially for Valentine’s Day; perfect for weddings. Plan to have companion plants to fill the gap after the bleeding hearts become dormant; hostas, toad lilies, astilbes, and balloon flowers are good choices.
‘Alba’ has pure white hearts dangling from it’s arching stems.
‘Gold Heart’. Pink hearts above deeply lobed golden leaves.
‘Valentine’ has white-tipped, cherry-red flowers on arching, deep burgundy stems. Foliage matures to dark gray-green.
Lamprocapnos spectabilis
Fabaceae
pea
Pictures of annual sweet peas (cultivars of Lathyrus odoratus) decorate the pages of seed catalogs, but there is a number of useful, though lesser known, perennial species of Lathyrus also. These share many virtues of their annual relatives, except fragrance: all but one perennial species bears scentless flowers. The perennials offer colorful, winged, pea-type blossoms suitable for cutting, attractive pinnately compound foliage, and a climbing, mounding, or sprawling habit of growth.
Propagate by seed sown in early spring; nick seed coat and soak seeds overnight before sowing. Divide in early spring.
Lathyrus latifolius
• pink, white
• early to late summer
• 6–9 ft. × 3–6 ft.
• sun
• Z3–8
Everlasting pea, perennial sweet pea. Native to southern Europe, this long-lived, rhizomatous perennial has naturalized in many regions of North America. It is considered invasive in Michigan, Wisconsin, and Oregon, but elsewhere, though introduced in the 18th century, it has not proven overly aggressive. The winged stems bear opposing pairs of oval, 3-in., medium green leaves. Leaflets often end in tendrils that wrap any available support to clamber to 6 ft. or more, or simply scramble along the ground. The 1-in., white or pink flowers are borne singly or in racemes of six to eleven. Flattened, pea-like seeds are enclosed in pods; toxic if ingested. Provide full sun or very light shade in open, airy spots, with moisture-retaining but well-drained soil. Best adapted to regions with cool summers; high humidity and stagnant air encourages fungal diseases. No serious insect pests; slugs and snails attack young plants. Appropriate for cottage gardens and other informal places where plants can sprawl along the ground, clothe a bank, or clamber up fences and walls. In borders grow up a tuteur or rustic tepee. Good in containers.
‘White Pearl’ (‘Pearl White’) bears pure white flowers; ‘Pink Pearl’ (‘Rosa Perle’) has pale pink flowers; ‘Red Pearl’ bears wine-red flowers.
Lathyrus vernus
syn. Orobus vernus
• reddish purple
• early to midspring
• 6–12 in. high and wide
• part shade, shade
• Z5–9
Spring vetchling. This European native forms bushy clumps of unwinged stems that bear racemes of 0.75-in., pea-type flowers in the leaf axils. Reddish purple flowers are veined with red, and mature violet-blue. Pinnate, light green leaves with 1.5- to 3-in., ovate leaflets. Flourishes in average soil that drains well. In warm climates foliage may die back as temperatures rise. Slow to establish, the roots resent disturbance. Use in cottage gardens, shady borders, and wild gardens. Typically pest and disease free, but the flowers are a delicacy for deer.
‘Alboroseus’ has exquisite white-and-pink flowers.
‘Alba’ is white flowered
f. roseus is pink flowered.
Lamiaceae
lavender
Few other perennials offer such a concentration of sensual gratifications as the lavenders. With their deliciously scented, silver-hued, evergreen foliage, lavenders reward eye, nose, and touch. Not surprisingly, they find many applications in the home as well as the garden. Lavenders have a reputation among gardeners for being finicky, but if a few basic cultural needs are met, they are reliable, relatively undemanding plants. Best of all, they are rarely molested by deer or rabbits.
Nearly all species of lavender originated around the Mediterranean. To grow them successfully, match the conditions in which they evolved as closely as possible: a well-drained, lean, sweet soil, with bright sunlight in an airy location; a Mediterranean-type climate of hot, dry summers and temperate, moister winters, as found in coastal California, is ideal. However, with excellent drainage lavenders also thrive in regions with cooler summers and cold winters; summer heat and humidity are problematic for most, as are heavy, water-retentive soils. Grow lavenders in raised beds or containers if necessary to enhance drainage; a lime chip or gravel mulch creates a drier microclimate at the crown (helpful in humid regions), and aids surface runoff. Different species of lavender vary in their climatic adaption—selecting the type best suited to your conditions is particularly important with this genus. Once established, lavenders are notably drought tolerant and perform very well in xeriscapes.
Where soils are heavy, improve drainage with coarse sand or grit, along with compost before planting. Avoid an overly rich diet that encourages soft, disease-prone growth and reduces the foliage fragrance, as the essential oils do not intensify. Maintenance includes an annual barbering just after new growth has appeared: cut back by a third to encourage compact, vigorous growth. Beware of pruning too early, as soft young growth may get frosted.
Lavender is an obvious choice for herb gardens; elsewhere they are outstanding planted as low hedges along pathways or to define garden spaces perhaps in containers, to furnish color and contrast in perennial and mixed borders, in rock gardens, or in fragrance gardens, especially those for the visually impaired. Dramatic when massed, lavenders respond well to the regular severe clipping demanded by topiary. Foraging bees and butterflies flock to the flowers; lavender honey is a gourmet item. The oils are used not only in toiletries, but are important in aromatherapy. Sachets of dried lavender retain their fragrance for several years providing a pleasant aroma to clothing, and also deter clothes moths. In the kitchen, flavor scones, cookies, and ice cream with the dried flowers.
Propagate hybrids and named cultivars by spring tip cuttings, or by mound layering; start species from seed sown indoors seven to ten weeks before the last spring frost.
• lavender, pink, white
• early to midsummer
• 2–3 ft. × 2–4 ft.
• sun
• Z5–8, HS
English lavender. Not of English origin but rather native to stony hillsides of the Mediterranean. Semi-woody, English lavender bears narrow, needle-like, gray-green leaves to 2.5 in. long on square stems. Tiny but abundant flowers are arranged in tight terminal spikes; corollas and calyces are frequently of contrasting hues. Both foliage and flowers are highly aromatic. Tolerates air pollution well.
There are many cultivars in the marketplace, mostly 18–24 in. This is a selection:
‘Compacta’ is well suited to low hedges. Extra-silver foliage; purple-and-violet flowers.
‘Hidcote’ (‘Hidcote Blue’) makes compact mounds; very dark purple-and-violet flowers. Slow growing; suitable for hedges.
‘Irene Doyle’ has especially fragrant, light purple-and-violet flowers; fall rebloom. Tolerates clipping well; good for hedges.
‘Loddon Blue’ has purple-blue flowers.
Lavandula angustifolia ‘Loddon Blue’
‘Munstead’ is compact with purple-and-violet flowers. Common in the nursery trade, but most plants sold under this name are seed propagated, and not uniform or true to type. Paler than ‘Hidcote’. Popular for culinary use.
‘Nana Alba’ is exceptionally compact, with pure white flowers. 1 ft. × 2 ft.
Lavandula dentata
• violet-blue
• early summer to fall
• 2–3 ft. × 4 ft.
• sun
• Z8–10, HS
French lavender. Not a French native, but from southern and eastern Spain, northwestern Africa, Ethiopia, Israel, Jordan, and the Arabian Peninsula. The bright green, 1- to 1.5-in. leaves are velvety, deeply toothed along the edges. Short, fat spikes of pale lavender-blue flowers are topped with light purple bracts. Fragrance is strong and herbal, intermediate between typical lavender and rosemary. Evergreen, blooms almost year-round in the southern part of its range.
‘Linda Ligon’ has white-and-green variegated foliage; mauve flowers. Unusual for hedges.
var. candicans has more silvery foliage than the species.
Lavandula ×intermedia
• pale lavender
• early to midsummer
• 2–3 ft. high and wide
• sun
• Z5–8, HS
Lavandin. A hybrid group originating from crosses of Lavandula angustifolia and L. latifolia. These highly fragrant plants form shrubby mounds of gray-green, needle-like leaves with 3- to 4-in. spikes of flowers. Evergreen in mild regions. Some growers report a better tolerance to heat and humidity than most other lavenders.
‘Alba’ is white flowered. 1–1.5 ft. × 1.5 ft.
‘Grappenhall’ has blue-purple flowers. Dries well. 3 ft. × 5 ft. Z5–11.
‘Grosso’. Silver-green foliage in 2- to 3-ft. mounds. Large, plump spikes of exceptionally fragrant, lavender flowers bloom above the foliage. Valued for its oil. Z5–11.
Lavandula ×intermedia ‘Grosso’
‘Phenomenal’ makes uniform mounds of silvery foliage that does not die back in winter. Resists foliar diseases and drought. 24–32 in. high and wide. Z4–8.
‘Provence’ is particularly aromatic; light lavender flowers on upright stems. 24–36 in.
Lavandula latifolia
syn. L. spica
• blue, purple
• late spring to late summer
• 3 ft. × 4 ft.
• sun
• Z6–8, HS
Spike lavender, Portuguese lavender. Native to central and eastern Spain, southern France, northern Italy. Similar to English lavender, but with coarser foliage. Blue-gray flowers carried on long, spiky stems. Fragrance is more camphor-like. Valued in soap and perfume industries, and for aromatherapy.
Lavandula stoechas
• pink, purple, lavender
• late spring to summer
• 1–3 ft. high and wide
• sun
• Z8–9, HS
French lavender, Spanish lavender, topped lavender. Mediterranean basin, southern Europe, northern Africa. Narrow, gray-green, 0.5- to 1.5-in. leaves; short-stalked, dense, pineapple-like heads of tiny, blackish purple flowers, topped by a tuft of purple bracts. Exceptionally heat and drought tolerant.
‘Lemon Leigh’ is lemon scented; white flowers topped with showy yellow bracts. 20–28 in. × 18–36 in. Z7–9.
‘Madrid Blue’ has sky blue flowers accented with upright white bracts. Early and compact; perfect for containers. 1–2 ft.
Lavandula stoechas ‘Madrid Blue’
‘Mulberry Ruffles’ is part of the Ruffles Series. Deep pink flowers. 2 ft.
Lavandula viridis
• yellow
• early to late summer
• 2–3 ft. high and wide
• sun
• Z8–10, HS
Yellow lavender. Mediterranean. Bright green foliage with a pine fragrance; flowers similar to Lavandula stoechas in form, but with creamy-yellow corollas and greenish yellow bracts. A striking contrast planted among other lavenders.
Malvaceae
tree mallow
Summertime trips to English gardens reveal an abundance of tree mallows, especially in larger landscapes that can accommodate these robust perennials. American gardeners, however, are only just starting to embrace these plants. Kissing cousins to hollyhocks, hibiscus, prairie mallows, and mallows, tree mallows bear similar five-petaled, open, funnel-shaped blossoms marked by a central column of joined stamens. The flowers are often accented with a darker-colored eye. The genus includes about 25 species, but few are garden-worthy perennials.
Lavateras thrive in light, sandy, moderately fertile, well-drained soil, in sites with full sun. Root rot may develop where soil drains poorly, and rust is sometimes a problem. Deer enjoy the soft young growth and the flowers. These plants are excellent at the back of perennial or mixed borders, and combine well with shrubs. Good for coastal gardens; protect from strong winds. Breeding programs have produced a number of hybrid cultivars, some of which are stunning, especially when sited carefully.
Propagate by seed, or take cuttings from young spring or early summer growth. Plants may be short lived; keep replacements on hand.
Lavatera cachemiriana
syn. L. cachemirica
• pink
• summer
• 4–8 ft. × 3–4 ft.
• sun
• Z4–9
Kashmir, India. Elegant and long blooming, this is a fine plant to back large borders and seldom needs staking. Softly hairy on top and downy beneath, heart-shaped leaves are rounded and lobed, to 3 in. long. Open, funnel-shaped, clear rosy pink flowers cluster in racemes in the upper leaf axils. The silky petals are deeply notched.
• rose pink
• summer
• 4–6 ft. × 5 ft.
• sun
• Z6–9
Tree mallow. Southeastern Europe. These plants need a large landscape, and do not show to best advantage when crowded. Erect stems, woody below and covered with fine gray hairs, carry long-stalked, 3.5-in., palmately lobed, heart-shaped leaves alternately along their length; basal leaves are entire. Purplish pink blooms to 3 in. across on long stalks are held singly in the leaf axils, or in loose spikes. Tolerates drought; appropriate for xeriscapes. A parent of many hybrids.
‘Ice Cool’ (‘Peppermint Ice’) has pure white flowers that may become pink tinged with age. Sensitive to mild, wet conditions in winter. Comes true from seed.
Lavatera thuringiaca
Other Notable Cultivars
Most hybrids are correctly known as Lavatera ×clementii but they are generally listed under L. thuringiaca. The other predominant parent is L. olbia. Mostly sterile.
‘Barnsley’, perhaps the best known of the hybrids, is named for Barnsley House, home of the late British garden designer and author Rosemary Verey. Flowers are 3–4 in. across, very light pink with a dark red-pink eye. 6–7 ft. ‘Barnsley Baby’ is probably a dwarf sport. 2 ft.
‘Bredon Springs’ has deep rose flowers with darker veins. 5–6 ft.
‘Candy Floss’ (‘Cotton Candy’) has grayish leaves, and bright pink, white-eyed flowers. 3–4 ft.
‘Red Rum’ blooms with magenta-red flowers on burgundy stems. Grayish, felted leaves. 4–6 ft.
‘Shorty’. This dwarf has light pink flowers on 18- to 24-in. stems. Suitable for containers.
Lamiaceae
motherwort
Homeopathic healers around the world use this herb medicinally, especially for the treatment of heart problems. Reputedly, the plant should be harvested at the peak of its bloom, as that is when the active chemical components are most potent.
Motherwort tolerates most soils, except those that become waterlogged. It may become invasive on good soils, and is perhaps best reserved for colonizing poor or stony soils in difficult sunny spots. Let it grow into quite large stands to make a visual impact. Fine in wild gardens; grow in containers in herb and medicinal gardens. Siberian motherwort, Leonurus sibericus, is similar but usually grows as a biennial.
Not browsed by deer or other mammals; pollinated by bumblebees and others. Seeds are often spread by attachment to animal hair.
Propagate by seed or by division of the rhizomatous clumps,
Leonurus cardiaca
• purple
• summer to fall
• 3–5 ft. × 3 ft.
• sun, part shade
• Z3–9
Motherwort, lion’s tail, heartwort. Europe, Mediterranean. Mostly sold as a medicinal herb, but it makes an attractive garden ornamental where space is not limited. Vigorous clumps of erect, square, purplish brown stems bear pairs of long-petioled, malodorous leaves, furry to the touch with soft hairs; the veins are conspicuously purple. Lower, deeply five-lobed leaves to 4 in. long, are further divided and toothed; smaller, coarsely toothed upper leaves are smooth, oblong to ovate. Clusters or whorls of two-lipped flowers nestle at the nodes; usually purple, pink, or white, the hairy upper lip is entire, the lower three lobed, often freckled with deep purple spots. Reseeds generously.
Leonurus cardiaca
Asteraceae
edelweiss
Edelweiss is a genus of 40 or so species, most of which grow wild in the mountains of Europe and Asia. One species, Leontopodium alpinum, is cultivated in gardens; it is the national emblem of Switzerland and Austria. The botanical name comes from the flowers’ fancied resemblance to a lion’s paw.
Propagate by seed sown as soon as it ripens in fall; overwinter in a cold frame or protected, unheated spot. Divide established plants in spring.
Leontopodium alpinum
• yellow
• midsummer to early fall
• 6–12 in. × 6–9 in.
• sun
• Z4–7, HS
Edelweiss. Alpine regions of southeastern and south-central Europe. It forms a mat of narrow, green leaves, felted with fine gray hairs. What appear to be individual flowers are in fact flowerheads, each composed of small, yellow disk flowers set into circles of showy white-woolly, fuzzy, petal-like bracts. Slow growing but gradually expands by rhizomes on hospitable sites. Provide very well-drained, sandy or gritty, neutral to alkaline soil; in the seeming contradiction exhibited by many alpine plants, the roots of edelweiss require regular moistening, but rot if consistently wet. A gravel topdressing speeds rain runoff from the crowns. Best adapted to cool-summer climates. Display this gem in rock gardens, alpine trough gardens, or containers.
Fabaceae
bush clover
Bush clovers are known for their racemes of small pea flowers, and their ability (as do all the pea family) to fix nitrogen in root nodules and thus improve the soil. Furthermore their deep roots help to control erosion. Of perhaps 40 species, only two are of note: Lespedeza bicolor is an invasive shrub planted as a forage crop and for its seeds to attract quail, pheasant, and other game birds. Lespedeza thunbergii, Thunberg’s bush clover, is a woody-based perennial that provides much-needed color to late summer and fall gardens.
Masses of pea-like flowers are borne in 6-in. racemes in the upper parts of the stems that bend under the weight of the flowers during bloom time. Where winters are mild, cut stems a few inches above ground level in early spring as new growth appears; in cold-winter regions (zones 4–6) most stems will die in winter, but new growth will emerge in midspring from the base.
Thunberg’s bush clover is not fussy about soil conditions. It does well in average soils, and thrives where soil tends to be poor; withhold fertilizer as it is seldom necessary and produces soft, rank growth. Drought tolerant when established, the deep roots are difficult to move; the plants resent disturbance.
The elegant arching habit of bush clovers is best seen from below. Plant them where the stems can cascade over a stone or brick wall, boulders, or a bank. They are suitable for planting among shrubs or at the back of mixed and perennial borders, as well as in wildlife gardens where they attract butterflies and bees. Although L. bicolor is planted to attract deer and rabbits, L. thunbergii is listed on many deer-resistant plant lists and the authors have experienced no deer browsing on several plants over many years. Ornamental grasses, Japanese anemones, Russian sage, and garlic chives are good companions.
Propagate by seed (scarify) or by soft cuttings in summer; start both in pots so as to avoid root disturbance when planting out.
Lespedeza thunbergii
syn. L. sieboldii
• purple, pink
• late summer to early fall
• 4–6 ft. × 4–8 ft.
• sun, part shade
• Z4–8
Thunberg’s bush clover. Japan, northern China. Fast-growing stems are clothed with alternate, trifoliate leaves, with oval, l- to 2-in. leaflets. Young leaves are silky silver, with hairs. The axils of the upper leaves host racemes of bloom over a long period; the weight of the flowers causes the stems to bend creating an unforgettable waterfall of color. Allow the stems to remain through the winter for their architectural effect. Where the stems are too woody to be winter killed, prune in early spring. This underused plant deserves a much wider appreciation.
‘Edo-Shibori’ is an unusual Japanese selection. Bicolored pink-and-white flowers. Can train as a standard. 5–6 ft.
‘Gibraltar’ has purple-pink flowers. 4–6 ft.
‘Pink Fountains’ has an arching habit and soft pink flowers. 4–5 ft.
‘Spilt Milk’ (‘Variegata’). Flowers are lavender, set against heavily cream-splashed leaves that provide long-term foliar interest. 4 ft.
‘Spring Grove’. Compact and well suited to smaller spaces. Deep purple flowers. 3 ft. tall.
‘White Fountains’ has white flowers that bloom earlier than ‘Albiflora’. Some consider it superior to the latter. 6 ft.
Asteraceae
oxeye daisy
Although closely related to chrysanthemums and many formerly classified in that genus, the 70 or so species in the genus Leucanthemum differ from their better-known relatives, lacking the pungent odor common in chrysanthemums and the grayish white hairs that clothe the leaves of “mums.” Additionly, they lack the broad palette of colors found in chrysanthemums—oxeye daisy flowers are almost universally white. However, as a reliable and prolific source of this invaluable hue (white is technically an absence of color), leucanthemums are unequalled among perennials. Their showy, gleaming blossoms help cool-summer gardens filled with hotter reds, oranges, and golds; they serve to separate or to transition between floral shades that would clash if placed side by side. White flowers show up particularly well in weaker evening light, and practically glow in nocturnal gardens.
Of all the leucanthemums worldwide, only one species and a race of hybrids derived from it have made it into American gardens. Oxeye daisy (L. vulgare) is a Eurasian native; it is almost unkillable and has escaped from cultivation to establish itself in the wild throughout North America. Its offspring is the much-loved Shasta daisy (L. ×superbum) created by prolific plant hybridizer Luther Burbank. His breeding program included L. vulgare, the English field or dog daisy, the Pyrenees daisy (L. maximum), Portuguese field daisy (L. lacustre), and the Japanese field or Montauk daisy (Nipponanthemum nipponicum, or Chrysanthemum nipponicum). Burbank named his new plants Shasta daisies. Many fine and diverse cultivars have since been created.
In general, leucanthemums are vigorous herbaceous perennials with daisy-like composite flowerheads, alternate leaves, and creeping rootstocks. All are fine cut flowers. Reliable, robust, and typically trouble free, oxeye and Shasta daisies are somewhat susceptible to verticillium wilt, leaf spots, and stem rots; they are occasionally targeted by aphids, mites, and leaf miners. Deer seldom browse them.
Propagate by seed or division.
Leucanthemum ×superbum
• white
• early to midsummer
• 8–48 in. × 12–24 in.
• sun, part shade
• Z5–8
Shasta daisy. Of hybrid origin. Alternate, glossy dark green leaves are oblanceolate to lanceolate, edged with coarse teeth. Typically flowerheads reach 2–5 in. across, with white rays surrounding a yellow disk. Bloom time lasts for about four weeks with intermittent bloom afterward; deadhead for further flowers. Best results are achieved in moist, rich, well-drained soil and full sun; provide partial shade on dry soils. Very prone to crown rot on wet or poorly drained soils. Mulch in winter with a loose blanket of evergreen boughs; avoid water-retentive mulch. Some cultivars may be hardier than zone 5, especially if drainage is perfect.
Leucanthemum vulgare
syn. Chrysanthemum leucanthemum
• white
• late spring to fall
• 1–3 ft. × 1–2 ft.
• sun
• Z3–8
Oxeye daisy. Native to meadows and fields, and in disturbed areas of Europe and Asia; naturalized throughout North America. Mostly unbranched stems rise from creeping, rhizomatous rootstocks. Dark green, long-petioled leaves are scalloped, obovate to spoon shaped toward the base; shorter, sessile, and shallowly lobed farther up the stems. Small flowerheads to 2 in. across have about 20 white, petal-like rays encircling a yellow disk. Spreading both by rhizomes and by seed, this species is considered weedy and invasive in many US states, particularly California, Montana, Arizona, Colorado, Tennessee, and Wyoming, where its cultivation is prohibited. Oxeye’s aggressive personality makes it unwanted in borders, but ideal for informal landscapes such as cottage gardens, wild gardens, meadows and naturalized areas.
Oxeye daisy thrives in average, well-drained soils, and prefers a moderately moist environment; tolerant of dry soils and drought once established. Provide light shade in hot-summer regions; deadhead to prolong bloom. Attractive to butterflies; resists rabbits and deer.
‘Maikonigin’ (‘May Queen’) is compact, with typical 2-in., white daisy flowers.
Other Notable Cultivars
The following hybrids all have white, petal-like rays and yellow central disks unless otherwise noted.
‘Aglaia’ bears 3-in.-wide, frilled, double flowers. 2 ft. tall.
‘Becky’ displays 3- to 4-in. daisies on rigid stems that do not need staking. Mid- to late summer. 3–4 ft. Excellent, long-lasting cut flower. PPA Perennial Plant of the Year for 2003.
Leucanthemum ‘Becky’ partners with Echinacea ‘Kim’s Knee-High’
‘Broadway Lights’. Single blooms open creamy yellow, mature to white. 18–24 in. Z6–9.
Leucanthemum ×superbum ‘Broadway Lights’
‘Goldrausch’ bears double, pale yellow flowers. 14 in.
‘Little Miss Muffet’ is compact, with 2-in., semi-double flowers. 1 ft.
‘Thomas Killen’ (‘T. E. Killen’) displays 3-in. flowers with a double row of white petals surrounding a crested, fluffy yellow center. Sturdy, 2.5-ft. stems.
Portulacaceae
lewisia, cliff maids
This North American genus of flowering succulents is named for the famed Meriwether Lewis, co-leader of the Lewis and Clark expedition. Lewisias are found in the wild in well-drained sites in the mountains of the northwest United States. They are much sought after, especially by alpine plant specialists who enjoy the challenge of nurturing them as much as for the beautiful flowers. Many species are very difficult to grow, but those outlined here are less temperamental. Wild populations of some species are under stress from overenthusiastic collectors and are now protected by law.
Typically, lewisias form basal rosettes of succulent, deciduous or evergreen leaves that arise from a fleshy taproot. The deciduous species, including Lewisia rediviva and L. longipetala, die back just after flowering and must remain dry while dormant, until the following spring.
Grow lewisias in rock gardens, between rock crevices, or, where the climate is unsuitable, in containers in alpine houses. They demand free-draining soil and a dry situation during the winter; quick to rot if roots remain wet. Gritty loam, lightly amended with coarse leaf mold or compost, is best for container-grown plants, and a similar mix is ideal for plants grown outdoors; pack the mix into vertical crevices and between rocks to ensure perfect drainage. Accelerate rain runoff with gravel mulch around the plant collars. Many do well with part shade, although a mostly sunny spot is usually fine.
Pests and diseases are few apart from stem rot; slugs, snails, and aphids may become a problem. Deer tolerant, but destroyed by voles.
Lewisia columbiana
• pink
• spring to summer
• 6–10 in. × 6 in.
• part shade
• Z4–8, HS
Columbian lewisia. Mountain regions of British Columbia, Washington, and Oregon. Evergreen and succulent, the leaves are linear to spatulate, to 3 in. long. Open sprays of pink-striped white or lavender to magenta, 0.5-in. flowers rise above the basal rosette.
‘Rosea’ has deep crimson-mauve flowers. Makes relatively large plants. 6–8 in.
Lewisia cotyledon
syn. L. finchae, L. purdyi
• white, yellow, orange, pink
• spring to early summer
• 9–12 in. × 8 in.
• part shade
• Z3–9, HS
Cliff maids, Siskiyou lewisia. Siskiyou Mountains of Oregon and south to northern California coastal ranges. This is the most widely grown species for its ease of cultivation outside its natural range. It hybridizes freely and many selections are available. Evergreen basal rosettes of 1- to 5-in.-long, fleshy, spoon-shaped leaves give rise to thick, branching stems topped with compact clusters of brilliantly and variably colored, open, funnel-form flowers, to 1 in. across.
The Cotyledon Hybrids Strain comes in assorted colors; evergreen. 6–12 in.
‘Little Plum’ (Lewisia longipetala × L. cotyledon), a hybrid, has succulent, evergreen leaves that reportedly are rot and pest resistant. Deep carmine-flushed pink flowers. 3–4 in.
‘Regenbogen’ has salmon and pink flowers.
Lewisia cotyledon
Other Notable Cultivars
Bright-Eyes has flowers in the usual colors, but with a conspicuous pale eye. 6–8 in.
Rainbow Dazzlers strain has white, yellow, orange, pink, or purple blooms. 8–10 in.
Sunset Strain produces 1-in. flowers in a range of colors from apricot and tangerine, through yellow to cream and pink. 6 in. tall.
Yellow Shades has flowers in various shades of pale lemon to gold. 8 in.
Asteraceae
blazing star, gayfeather
Expect fireworks when you include blazing stars in your planting: the spikes of vivid flowers that shoot up from the clumps of whorled, narrow foliage are like slow-motion rockets. Natives of New World grasslands, liatris have evolved to raise their heads above their neighbors, making them wonderful accent plants for sunny borders, as well as ideal vertical punctuation in meadow or prairie plantings. The striking look and form of the flower spikes makes blazing stars a good source of cut flowers that open gradually; their display, whether in a vase or in the garden, is long lasting.
Flower spikes are composed of multiple, closely set, button-like buds that open to produce a fluffy effect. Unusually, these open from the top down; in floral displays the spent tops can be snapped out, allowing for a longer vase life.
Like so many prairie and grassland plants, liatris have the ability to cope with adverse conditions: their cormous roots withstand prolonged drought, as well as summer heat and humidity, and winter cold. They thrive on moderate to nutrient-poor soils, as long as drainage is good; not tolerant of poorly drained, wet soil, especially in wintertime. Liatris blooms attract butterflies and hummingbirds, and later the seeds provide fall food for a variety of birds. Taller species and cultivars may require staking. They resist deer, and suffer from no serious pests and diseases.
Propagate by seed sown in fall as soon as it ripens; overwinter outdoors. Dig and divide corm clumps in late winter before they break dormancy. Softwood cuttings root readily in spring.
Liatris aspera
• purple
• late summer to early fall
• 2–5 ft. × 1–1.5 ft.
• sun
• Z3–8
Rough gayfeather. Native to dryish soils in prairies, open woods, meadows, and along roads and railroad tracks throughout Eastern and Midwestern North America. This species produces basal tufts of rough, narrow, lanceolate leaves sometimes 12 in. long. Erect, leafy stalks rise from the base, topped with long spikes of rounded, fluffy, rose-purple flowerheads, each up to 0.75 in. across. Tolerates shallow, rocky soils.
Liatris microcephala
• purple
• mid- to late summer
• 18–24 in. × 12–18 in.
• sun, part shade
• Z4–7
Dwarf blazing star. Native to southern Appalachians. Basal rosettes of grassy leaves from which emerge several 12- to 24-in. spikes of rosy-purple flowerheads. A good species for planting among boulders in rock gardens or in the foreground of sunny borders.
Liatris pycnostachya
• purple
• early to late summer
• 2–5 ft. × 1–2 ft.
• sun
• Z3–9
Prairie blazing star. Native to central and southeastern United States. This robust, grassland perennial produces clumps of narrow, lanceolate leaves, to 12 in. long; fluffy flowerheads are deep rose-purple, to 0.75 in. across; they are borne in dense terminal spikes to 20 in. long. Tolerates well-drained clay or poor soils, and summer heat and humidity. Prairie blazing star may be too large and vigorous for most borders, but it is an asset in wild and native plant gardens, naturalized areas, prairie plantings, and meadows.
Liatris scariosa
• purple
• late summer to midfall
• 2–4 ft. × 1–2 ft.
• sun
• Z3–8, HT
Blazing star. Native to rocky woods and slopes, grasslands, and gravelly streambanks from Maine, west to Wisconsin, and south to Mississippi and Georgia. Produces basal tufts of rough, narrow, ovate to lanceolate leaves, to 10 in. long; leaves become smaller as they ascend the stem. Fluffy, reddish purple flowerheads to 1 in. across top erect stems in columnar spikes, to 18 in. long. Prefers dry, sandy, or rocky soils; staking may be necessary if grown on more fertile soils. Intolerant of wet feet, especially in winter. May self-seed on favorable sites. Blazing stars are an excellent choice for borders, cottage gardens, meadow and prairie plantings, and naturalized landscapes.
Liatris spicata
syn. L. callilepis hort.
• purple
• midsummer to early fall
• 3–5 ft. × 2 ft.
• sun, part shade
• Z3–9, HT
Spike gayfeather, button snakeroot, dense blazing star. Native to low, moist sites throughout the eastern and southern United States. Grass-like leaves to 12 in. long are arranged in basal tufts; tall stems are topped with 6- to 12-in., terminal spikes of fluffy, mauve to deep purple flowerheads, to 0.75 in. in diameter. Spike gayfeather prefers moist, organic-rich soil, but ordinary garden soil suffices. It handles more moisture than other members of the genus; also tolerant of poor soil, heat, humidity, and drought. A favorite of the floral industry, a natural for cutting gardens, and as vertical accents in borders or damp meadows.
‘Blue Bird’ has blue-purple flowerheads
‘Kobold’ is compact, 2–2.5 ft., with deep purple flowerheads.
‘Snow Queen’ has white flowerheads.
Liatris spicata
Iridaceae
libertia
These iris relatives are winter hardy in warmer zones; in colder regions they make excellent container plants that can overwinter indoors and be set out to decorate late spring and summer gardens. Most libertias are native to damp, grassy scrubland of New Zealand and Australasia, but some hail from Chile and other temperate parts of South America.
Arising from short rhizomatous roots, libertias’ evergreen, slender, and grass-like leaves grow in two overlapping ranks or fans, forming thick clumps. The leaves are often colorful, some are exotically striped. Attractive blooms are borne in loose sprays that cluster into panicles. The saucer-like flowers consist of a double ring of three petal-like structures (tepals); sometimes the outer ring is greenish. Colorful orange, yellow, or black seeds follow.
Libertias are great additions to beds and borders, and provide a structural foil for rounded sedums, phlox, daisies, and other perennials both in and out of bloom. In containers they fill the role of “thrillers” and can be assorted with lower, more rounded “fillers”—geraniums, salvias, and osteospermum—along with trailing “spillers” such as Origanum ‘Kent Beauty’. In rock gardens libertias bring a change of height to the usual display of low “bun” plants and creepers.
Provide a sunny or partly sunny spot for these beauties. Soil should drain well, but retain moisture, enriched with compost. Mulch in winter where marginally hardy, or bring containers indoors to a cool, frost-free spot. The woody rhizomes resent disturbance, so when planting libertias set them into what will be their permanent home. Libertias are not successful in hot gardens, except where humidity is low, as in California. Seldom browsed by deer; susceptible to slug and snail damage.
Divide clumps in spring or start from seed; seedlings take two to three years to reach blooming size.
Libertia formosa
syn. L. chilensis
• white
• late spring to midsummer
• 2–3 ft. × 2 ft.
• sun, part shade
• Z7–11, HS
Showy libertia, snowy mermaid. Chile. Dense tufts of stiff, wide, leathery, 0.5-in. × 12- to 18-in. leaves. Strong scapes lift 1-ft.-long inflorescences, composed of dense clusters of 0.75-in. flowers, above the foliage mass. Long blooming. Prefers acid soil. This species has escaped in the San Francisco Bay area. Attracts butterflies, bees, and birds. Good for rock gardens.
Libertia ixioides
• white
• late spring to early summer
• 1–2 ft. × 2 ft.
• sun, part shade
• Z8–11, HS
New Zealand iris, mikoikoi, tukauki. New Zealand. This clump-forming perennial provides structure and texture to gardens. The slender, grassy leaves are arranged in a fan, and are bronze, green, or chocolate-brown, paler along the midrib. Umbel-like clusters of two to nine white flowers form large substantial panicles of bloom among the foliage. Flowers may reach 1 in. across with white inner tepals and brownish green outer ones. Seedpods are yellow with orange seeds.
‘Sunset Blaze’ has fans of burgundy, orange, and gold leaves. Flowers held just above the foliage. 18–24 in. Z7–11.
‘Taupo Blaze’ is a selection of ‘Taupo Sunset’. Red-and-copper-colored leaves, greenish at the base especially in summer. Flowers held just above the leaves. Yellow-orange seedpods. 18 in. Z8–11.
‘Taupo Sunset’ produces its white flowers in summer. Stiff, grass-like leaves are striped with green, yellow, orange, purplish red, and bronze—hence its name. Excellent beside a pool or in mixed borders. 2 ft. Z7–11.
Other Notable Cultivars
‘Amazing Grace’ is easy. Olive-green to bronze leaves. Airy sprays of white flowers. 30 in. Z7–11.
‘Tricolor’. Olive leaves striped with cream; often turns reddish in cold weather. White flowers. 8–18 in. × 24 in. Z7–11.
Asteraceae
leopard plant, golden groundsel
These statuesque, dramatic plants are especially well suited to damp, partly shaded sites, such as rain gardens and watersides. They develop large clumps of rounded, heart-shaped, or arrowhead-shaped leaves, often held on dark stems. Several are grown especially for their amazing foliage; others also have attractive floral displays.
These water-loving plants demand soil that remains moist constantly, preferably enriched with humus or compost; avoid standing them in water. Ligularias are extremely sensitive to hot sun, even when the roots are damp; on sunny days, the large leaves often droop like elephant ears, only to recover at dusk. This is stressful for the plant. Select a growing spot with protection from noonday sun, ideally with light, dappled shade. Apply organic mulch to help retain moisture during the summer.
Good companions for ligularias (especially in deer country) include cinnamon and ostrich ferns, water irises, cardinal flower, and snakeroot. Boggy areas and open woodlands are ideal places for ligularias; shady north-facing beds and borders are appropriate if irrigation is available. Smaller sorts are ideal for the margins of miniature water gardens.
The conditions favored by ligularias are also ideal for slugs and snails that attack the young growth, disfiguring the foliage badly. Otherwise serious pests or diseases are few. All species resist deer browsing.
Sow seed in spring or fall; divide species and selections before bloom in spring or after flowering.
Ligularia dentata
syn. Senecio clivorum
• orange
• early to midsummer
• 3–4 ft. × 3 ft.
• part shade
• Z3–8
Leopard plant, big leaf ligularia. China, Japan. Basal clumps of long-stalked, leathery foliage is the main attraction of this plant. Dark green and coarsely toothed leaves, to 1 ft. long. Thick, fibrous stems carry loose clusters of untidy, yellow-orange, 3-in. daisy flowers. Largely replaced by superior cultivars.
‘Britt-Marie Crawford’. Shiny, kidney-shaped leaves of blackest purple, to 7 in. long. Yellow-orange flowers rise above the foliage mass. More sun tolerant than some. 2–3 ft. Z4–8.
Ligularia dentata ‘Britt-Marie Crawford’
‘Dark Beauty’. Very deep purple leaves on purple stems. Gold flowers. 3–4 ft. Z3–8.
‘Desdemona’. Serrated, kidney-shaped leaves are red, but mature to green with persistent purple undersides. Purple-stemmed, ragged, yellow-orange daisies. 2–3 ft. Z3–8. ‘Othello’ is similar.
Ligularia przewalskii
syn. Senecio przewalskii
• yellow
• mid- to late summer
• 5–6 ft. × 3 ft.
• part shade
• Z4–8
Shavalski’s ligularia. Northern China. Black stems clothed with triangular, palmately lobed, 12-in.-long leaves, deeply and irregularly cut. Narrow, loose racemes of yellow flowerheads rise on dark greenish purple stems.
‘Dragon’s Breath’. Exotic-looking clumps of very deeply cut, dark leaves. Spikes of bright yellow flowers on purple stems, early. 24–30 in. Z4–9.
Ligularia stenophylla
• yellow
• early to late summer
• 4–5 ft. × 5 ft.
• part shade
• Z5–8
Narrow-spiked ligularia. Northern China, Japan. This species is similar to Ligularia przewalskii, but has heart-shaped leaves and paler stems. Tall, slender racemes of few-rayed, yellow flowerheads, to 1.5 in. across.
‘Chinese Dragon’ has bold, deeply cut leaves, serrated along the edges. Clusters of few-rayed yellow flowers top each stem. Very attractive to butterflies. 3–4 ft. Z4–8.
‘Little Rocket’ is a dwarf form of ‘The Rocket’. Slender racemes of yellow flowers. Late summer. 3–4 ft. Z4–8.
‘The Rocket’. Early summer spikes 18–24 in. long held above the mass of dark green, jagged-edged leaves on black stems. 4–5 ft. Z5–8.
Other Notable Cultivars
‘Gregynog Gold’ (Ligularia dentata × L. veitchiana). Substantial green, heart-shaped leaves, rimmed with sharp teeth. Broadly conical clusters of orange daisies. 4–6 ft. Z4–9.
‘Last Dance’ is compact with bold, heart-shaped, dark green foliage beneath loose clusters of dark-centered yellow daisies. The last to bloom. 12–18 in. Z4–8.
‘Osiris Café Noir’ has thick, serrated olive, purple, or brown leaves topped by yellow daisy flowers. Introduced by Serge Fafard. Z4–8.
‘Osiris Fantaisie’. Clumps of rubbery, dark green, heart-shaped leaves with undulating jagged edges, on purple stems; undersides are burgundy. Sturdy branching stems hold 2- to 3-in., double, deep yellow daisies just above. Mid- to late summer. 2–3 ft. Z3–8.
Plumbaginaceae
statice, sea lavender
Best known as a source of cut flowers, this genus is an obvious choice for cutting gardens but can also serve as a useful source of summertime color in perennial borders.
Many species of statice originated in coastal habits and their tolerance for salt, wind, and sandy soils make them well adapted to seaside gardens and other exposed sites with poor, saline, or alkaline soils.
Do not crowd plants and ensure good air circulation to minimize susceptibility to crown and root rot. Seldom attacked by pests and diseases, including deer. The flowers retain their form and color when dried.
syn. Statice perezii
• purple
• spring to summer
• 3 ft. × 2 ft.
• sun
• Z9–10
Perez’s sea lavender. Canary Islands. Tough perennial herb arising from woody rhizomes. Oval to round leaves to 12 in. long are borne in basal rosettes; bushy panicles of white flowers with lavender sepals. Naturalized on beaches and roadside areas of coastal southern California but striking when massed in beds, on banks, or as accents among bold-leaved tropicals. Reliable for seaside plantings, and good for containers.
Limonium perezii
Limonium platyphyllum
syn. L. latifolium, Statice latifolia
• blue
• early to midsummer
• 2–2.5 ft. high and wide
• sun
• Z3–10
Sea lavender, perennial statice. Southeastern and central Europe. Basal rosettes of oblong-elliptic, leathery, deep green leaves to 10 in. long; tiny, lavender-blue flowers bloom in rounded, cloud-like panicles atop wiry stems. Flourishes on well-drained, average garden soil but tolerates droughty, rocky, and shallow soils too. May self-seed.
Plantaginaceae
toadflax
This genus includes roughly 100 species, including a few that are garden worthy and not aggressive. On the other hand it has contributed some seriously invasive species to the North American landscape. Linarias hail from southern Europe, inhabiting chiefly dry, sunny sites often with very poor soil where they tend to seed about freely. These characteristics are problematic in enabling yellow toadflax (butter-and-eggs, Linaria vulgaris) to spread along roadsides and in waste places almost everywhere in North America; the yellow-flowered Dalmatian toadflax, L. dalmatica, has become a serious weed in Washington, Idaho, Utah, and Arizona where it crowds out native species.
Typically linaria produces upright branching stems, clothed with linear to lance-shaped, often grayish green leaves. Toadflax flowers are spurred and two-lipped, and are borne abundantly in most colors of the rainbow. Though short-lived perennials, the garden toadflaxes are easily lifted as seedlings for replanting wherever needed to fill a gap. In warmer regions they are generally treated as winter annuals.
Toadflaxes prefer sunny sites with average but sandy soil. Drainage must be good to avoid root and stem rot. Drought and deer tolerant, these charming plants are appropriate for cottage gardens, for grouping in beds and borders, or lining out along pathways. They make good filler for containers, and the flowers attract pollinating insects including bees and butterflies, so they are well suited to wildlife gardens and meadow plantings too. Combine with more substantial plants such as Shasta daisies, sneezeweed, and summer phlox.
Propagate by seed.
Linaria alpina
• violet-and-yellow
• summer
• 4–8 in. × 6 in.
• sun
• Z4–8
Alpine toadflax. Native to mountainous regions of southern and central Europe. Often grown as an annual, this species is fully perennial but may burn out in hot summer regions. The linear leaves are blue-green arranged in whorls or alternately on trailing stems. Best in well-drained rock gardens, these diminutive plants are colorful all summer long with spurred bicolored or all pink, white, or yellow blooms.
Linaria purpurea
• purple
• early summer to fall
• 1.5–3 ft. × 1 ft.
• sun, part shade
• Z5–9
Purple toadflax. Sicily, central and southern Italy. This beautiful clump-forming self-seeder is a boon to gardeners who may have holes to fill in their summer flowerbeds; transplant small plants only. Long spikes of 0.3-in., purple or lilac flowers top erect stems clothed with slender, gray-green foliage, a perfect foil for the blooms. Cut back after the first flush to reduce self-seeding and to encourage further flowers.
‘Canon J. Went’ has pale pink flowers. Comes true from seed.
‘Springside White’ is white flowered.
Linaria triornithophora
• purple, yellow
• late spring to fall
• 3–4 ft. × 1 ft.
• sun, part shade
• Z6–9
Three-birds-flying. Spain, Portugal. This toadflax, with its appealing common name, makes mounds of blue-green leaves borne in whorls on erect, branching stems. In season, the foliage mounds are crowned with flocks of bird-like, 2-in. flowers with long, tail-like spurs, grouped in threes. The blossoms vary in color and are often two toned. Best in rich, well-drained soil. Often grown as a summer annual north of its area of hardiness.
‘Pink Birds’ may be hard to find. It has soft pink flowers on 18-in. stems.
Linaceae
perennial flax
Common flax (Linum usitatissimum), the source of linen and of flax seed, is the best-known member of this genus, which also includes some garden-worthy perennial species. Perennial flax are long blooming, and supply some of the garden’s most vivid blues. Individual blooms open early on sunny days but often are spent by late afternoon. Flax prefers lean, well-drained soils. They may self-seed.
Propagate by seed, by cuttings of young basal shoots in spring, or divide mature plants.
Linum flavum
• yellow
• summer
• 10–12 in. × 8–12 in.
• sun
• Z5–7
Golden flax, yellow flax. Native to central and southern Europe. Upright clumps, sometimes woody at the base, are clothed with dark, spoon-shaped foliage. Funnel-shaped, upward-facing, bright yellow flowers to 1 in. across are arranged in dense terminal cymes.
‘Compactum’ is only 6 in. tall.
Linum lewisii
syn. L. perenne subsp. lewisii
• blue
• late spring to early summer
• 12–24 in. × 8–12 in.
• sun
• Z3–9
Prairie flax, Lewis’s blue flax, western blue flax. Native to grasslands, meadows, and disturbed soils throughout the United States west of the Mississippi River. Species named for its discoverer, Meriwether Lewis, co-leader of the Lewis and Clark Expedition. This short-lived native bears needle-like, blue-green leaves and five-petaled, 2-in.-wide, sky-blue flowers that open fully only on sunny days. Deer tolerant, but slugs, snails, and aphids may be troublesome; attracts butterflies. Susceptible to stem rot, rust, damping off, and other fungal and bacterial problems. Appropriate in dry, sunny meadows, prairie and perennial plantings, open woodlands, rock gardens, and containers.
Linum lewisii
Linum narbonense
• blue
• late spring to early summer
• 18–24 in. × 15–18 in.
• sun, part shade
• Z5–9
Spanish blue flax. Native to northern Spain. Narrow, gray-green leaves arranged in whorls around the stems, topped by cymes of about ten saucer-shaped, five-petaled, 1-in., sky blue flowers accented with white eyes. Supposedly longer lived than more common Linum perenne. Ideal along paths, among rocks on sunny slopes, and in dry gardens.
‘Heavenly Blue’ has deep blue, white-eyed flowers. 18 in.
Linum perenne
• blue
• late spring to early summer
• 1–2 ft. × 9–18 in.
• sun, part shade
• Z5–8
Perennial flax, blue flax, perennial blue flax. Europe, temperate Asia. Short-lived, tufted perennial with wiry stems and narrow, linear leaves to 1 in. long. Funnel-shaped, sky blue flowers, borne prolifically for eight weeks or more, are five-petaled, to 0.75 in. across. Tolerates dry, shallow, and rocky soils; naturalizes where conditions are suitable. Mass for best displays in rock gardens, meadows, and herb gardens.
‘Appar’ has outstanding vigor, a long season of bloom, and is a strong reseeder that mixes well with grasses and other wildflowers in erosion control mixes.
‘Nanum Diamond’ shows off clean white flowers. 10–12 in.
‘Nanum Sapphire’ bears bright blue flowers on 8–10 in. stalks.
Asparagaceae
lilyturf, monkey grass
Problem solvers rather than garden stars, the lilyturfs nevertheless can be attractive when used in the right spot and the right way. These low, grass-like plants from eastern Asia combine glossy foliage with grape hyacinth–like spikes of late-summer flowers in purples, blues, or white. Evergreen in hot and humid climates, but elsewhere foliage browns—refresh by mowing on a high setting in early spring.
Lilyturfs prefer moist, fertile soils in part shade but will grow in any average, well-drained soils, in full sun. Tolerates heat, humidity, and drought and air pollution; resistant to rabbits, but susceptible to slugs and snails. Deer resistance is spotty; reports stating that deer devour liriope are countered by others reporting no damage at all.
Lilyturfs have a naturally neat, almost dapper, appearance that makes them perfect for edging paths or beds in formal landscapes, as well as a handsome and durable groundcover. Has proven invasive in parts of the southeastern United States.
Propagate by division.
Liriope muscari
• lavender
• late summer
• 12–18 in. × 9–12 in.
• sun, part shade
• Z6–10
Lilyturf. China, Taiwan, Japan. Tuberous rooted, forms slowly expanding clumps of strap-like, arching, glossy dark green leaves to 1 in. wide. Erect spikes with tiered whorls of violet-purple flowers similar to those of grape hyacinths emerge above foliage in late summer. Persistent black berries follow. Survives in sheltered locations in zone 5.
‘Big Blue’ has 15- to 18-in.-long leaves; violet flowers.
‘Monroe White’ has white flowers.
‘Pee Dee Gold Ingot’ produces yellow young foliage that deepens to gold or chartreuse, holding color year-round. Lavender flowers.
‘Silvery Sunproof’ has green-and-white-striped foliage; lavender flowers. More sun tolerant than other cultivars.
‘Variegata’ has green-and-white-striped leaves; lavender flowers.
Liriope spicata
• blue, white
• late summer
• 9–18 in. × 1–2 ft.
• sun, part shade
• Z4–10
Lilyturf. China, Vietnam. Forms grass-like clumps of narrow, arching, glossy dark green leaves to 0.25 in. wide; erect spikes of small, pale lavender to white flowers borne among the leaves; blackish berries follow. Spreads quickly by underground rhizomes and can be aggressive. Outstanding as a groundcover under shallow-rooted trees, along streams and ponds, and for stabilizing soil on erosion-prone banks and slopes.
‘Silver Dragon’ has leaves striped with green-and-silver-white; pale purple flowers; whitish green berries.
Boraginaceae
lithodora
The brilliant blue-flowered lithodoras are somewhat fussy and do best in the mild, maritime climate of the Pacific Northwest. However, given good conditions they grace many an alpine house, raised bed, trough, or rock garden elsewhere, and they can also serve as low-maintenance groundcovers. The plants are somewhat woody subshrubs, low growing or even prostrate, sometimes trailing.
Lithodoras demand very well-drained, neutral to alkaline soil, easy to achieve with a topdressing of lime chips around the crown. Under less than ideal conditions, branches may begin to blacken and die back; cut out damaged material. Even apparently thriving plants may die out in the center; replant with young plugs. Prune after bloom time annually to maintain vigor and control sprawling stems. The roots resent disturbance (buy container-grown plants), but if necessary should be moved during dormancy, when ground is not frozen; bare-root plants are seldom successful. Salt, deer, and drought tolerant. No serious pests and diseases.
Propagate by taking half-ripe cuttings preferably with a “heel” in summer. Seeds are slow and must be soaked or scarified prior to spring sowing.
Lithodora diffusa
syn. Lithospermum diffusum
• blue
• late spring to summer
• 4–8 in. × 18 in.
• sun
• Z5–7, HS
Indian plant, trailing lithodora. Southern and western Europe. An evergreen, ground-hugging subshrub, with alternate, hairy, narrowly oval leaves to 1.5 in. long. Terminal and axillary clusters of funnel-shaped, 0.5-in., brilliant blue flowers cover the plants for several weeks. Intolerant of high heat and humidity. Susceptible to freeze burn if temperatures plummet. One of only a few perennials with truly blue flowers.
‘Grace Ward’ has terminal clusters of azure blue flowers on trailing plants. Good for containers.
Lithodora diffusa ‘Grace Ward’
‘Heavenly Blue’ has deep azure flowers. Provide compost-rich, acid soil.
‘White Star’ has blue flowers with conspicuous white centers.
Campanulaceae
lobelia
Although best known for the ubiquitous annual trailing lobelia, this genus includes several outstanding perennial species and hybrids too. These North American natives are adapted to moist and wet soils, but will flourish in an average, organic-enriched garden soil, if irrigated conscientiously. These lobelias offer a combination of upright growth and bright flowers that make them very effective punctuation points in native plant gardens, mixed borders, and wild gardens; they spread to make bold statements in wet soils beside ponds and streams, or in bog gardens. Rabbit resistant but not reliably deer resistant, they attract butterflies and hummingbirds; excellent as cut flowers.
Propagate by seed, division, or cuttings taken in midsummer.
Lobelia cardinalis
• red
• mid- to late summer
• 2–4 ft. × 1–2 ft.
• sun, part shade
• Z3–9
Cardinal flower. North America, from southeastern Canada through the eastern and southwestern United States, Mexico, and Central America to northern Colombia. Clumps of upright stems clothed with dark green, finely toothed, lanceolate leaves to 4 in. long; stems are topped with spikes of bright red, 1- to 2-in.-long, tubular flowers. These are two lipped; the three lower-lip lobes are more prominent than the two lobes of the upper lip. Somewhat short lived, but reseed readily where conditions are favorable, typically along streams, wooded bottomlands, and swamps. Supply midday shade in hot and humid regions.
‘Alba’ has white flowers.
‘Angel Song’ has salmon-and-cream flowers.
‘Fried Green Tomatoes’ has purple young leaves that age to green with purple highlights; tomato-red flowers.
‘Queen Victoria’ (syn. Lobelia fulgida or L. fulgens ‘Queen Victoria’) has burgundy to dark purple foliage; red flowers.
‘Ruby Slippers’ has dark ruby-red flowers. Z4.
‘Twilight Zone’ is pink flowered.
Lobelia siphilitica
• blue, white
• mid- to late summer
• 12–36 in. × 12–18 in.
• sun, part shade
• Z4–9
Great blue lobelia. Wet locations and low wooded areas in Missouri. Similar to cardinal flower but with light green leaves to 5 in., and variably light to dark blue flowers. The botanical name recalls a former use of this plant as a treatment for venereal disease; it has a long history of medicinal use. Longer lived than Lobelia cardinalis. Self-seeds in hospitable sites.
‘Alba’ has white flowers.
‘Lilac Candles’ is compact, to 18 in., with lilac flowers.
Other Notable Cultivars
The following all bloom in late summer. Z3–8.
‘Dark Crusader’ has deep purplish foliage; magenta-purple flowers. 3 ft.
‘Gladys Lindley’ is white flowered. To 4 ft. tall.
‘Red Beauty’ has pinkish red flowers. 2–3 ft.
×speciosa ‘Vedrariensis’ has red-tinged foliage; bright purple flowers. 2–4 ft. tall
Brassicaceae
honesty, silver dollar plant
The name “lunaria” derives from “luna,” the Latin word for moon, inspired by the glistening seedpods (or silicules) that honesty bears. Although there are three species in the genus, only biennial honesty, also known as silver dollar plant, actually has round, truly “moon-like” seedpods. When the pods ripen, the seeds are shed, leaving their papery membrane intact.
Honesty prefers an organic-rich soil that drains well, and a sunny to partly shaded position. Full sun is fine in regions with low light, but where sunlight is intense noonday shade is beneficial. Pests and diseases are infrequent although stem rot may be a problem where drainage is poor. Occasionally browsed by deer.
A useful addition to informal beds and borders, bright woodland gardens, and naturalized semi-wild areas, honesty is perhaps most valuable as a dried cut flower. It is perfect in winter arrangements and does not shatter easily. Cut when the seedpods are green.
Propagate by seed or allow existing plants to self-seed.
Lunaria annua
• purple
• spring
• 2–3 ft. × 2 ft.
• part shade
• Z4–8
Honesty. Europe. In spite of its specific epithet, “annua,” honesty is actually biennial and seeds about so readily that it appears to be perennial. Alternate, heart-shaped, coarsely toothed leaves clothe upright stems. Flower petals, arranged in a cross, are usually in shades of purple, although they vary and often white-flowered plants appear. Circular, 2-in. seedpods follow.
‘Alba’ is white flowered.
‘Variegata’ has purple or sometimes white flowers; leaves irregularly rimmed with white.
• pale lilac
• late spring to early summer
• 2–3 ft. × 2 ft.
• sun, part shade
• Z5–8
Perennial honesty. Native to mountain areas of central Europe, western Siberia, the Baltic states, and Scandinavia. Erect and hairy, branching stems carry mid-green, finely serrated, triangular, 8-in.-long leaves, sometimes tinged with maroon. Fragrant, 1-in., pale lilac or whitish flowers with a lilac blush are arranged in loose racemes, sometimes 7 in. long. The flat, white, 2- to 3-in.-long seedpods that follow are elliptical and translucent; they become light tan at maturity.
Lunaria rediviva
Fabaceae
lupine, lupin
The name lupine derives from the Latin word for “wolf,” recalling an old-time belief that these plants devoured the richness of a soil. In fact, the opposite is true: lupines are found mostly on poor, sandy soils, but their roots have the ability to convert atmospheric nitrogen into plant nutrients. This trait is common to pea family members.
These desirable, though often short lived, perennials, combine handsome, typically fingered, palmately divided leaves with spires of colorful, pea-type flowers. The species are best grown on loose, very well-drained, lean soils similar to those of their native habitats. The showier and somewhat longer-lived garden hybrids, however, perform best on humus-rich, moderately fertile, well-drained soils. Avoid excessive fertility, which when combined with winter wet is likely to prove fatal.
In addition to perennial species, Lupinus includes some annuals (notably Texas bluebonnet) and shrubs. The perennial hybrids are ideal for creating rhythms of late spring color and texture, providing a pleasant contrast to bulbs or other perennials; the dense foliage remains attractive all season. The species are better suited to meadow or prairie plantings—care should be taken, however, to keep them out of pastures as they are toxic to grazing animals. Lupines are not trouble free, though the reward is worth the extra effort. In wetter climates, they are prone to slugs and snails when young, and susceptible to powdery mildew and aphids as well; serious infestations should be dealt with by cutting plants back almost to the ground. Stake taller types. Attracts butterflies; deer resistant.
Propagation by seed is most successful: scarify seeds and soak overnight before sowing.
Lupinus arboreus
• yellow, blue
• late spring to early summer
• 3–5 ft. high and wide
• sun, part shade
• Z8–10
Bush lupine, tree lupine. Western North America. Fast-growing, semi-evergreen, shrubby perennial with palmate leaves and erect, 10-in. racemes of fragrant, yellow flowers. Drought resistant; excellent for dry and coastal gardens. A parent of many garden hybrids.
Lupinus perennis
• blue, purple
• late spring
• 1–2 ft. × 1 ft.
• sun
• Z3–8
Sundial lupine, wild lupine. Maine to Florida. Dense mounds of palmately divided leaves, each with seven to eleven leaflets, to 2 in. long. Terminal, 8-in. racemes of light blue to purplish flowers; 2-in., bean-like, seed-filled pods follow. Flourishes on sandy, nutrient-poor and drought-prone soils; dislikes clays and loams.
Lupinus polyphyllus
• blue, purple, reddish, white
• late spring to early summer
• 3–5 ft. × 2–2.5 ft.
• sun
• Z4–7, HS
Bigleaf lupine. Western North America. Robust, with bold, rich green, palmate leaves each with 5 to 18 leaflets to 6 in. long, and imposing 12- to 28-in.-long racemes of 0.5-in. flowers on mostly unbranched stems. Has escaped gardens to become a troublesome weed in pastureland in the upper midwest and northeastern United States. Best adapted to regions with cool summers. A parent of many garden hybrids.
Other Notable Cultivars
‘Chandelier’ has yellow flowers; repeat blooms if deadheaded. 40 in. × 18–24 in. Z4–8.
‘Chatelaine’ has dense racemes of bicolored, pink-and-white flowers on 3- to 4-ft. stems. Z3–7.
Gallery Strain is compact, 15–18 in., with white, blue, pink, red, and yellow flowers. Z3–7.
‘My Castle’ has fragrant, scarlet flowers: repeats if deadheaded. 40 in. × 18–24 in. Z4–8.
Russell Hybrids bear spikes of flowers in shades of pink, red, yellow, blue, and white, often bicolored, in early and midsummer. 2.5–3 ft. × 1–1.5 ft. Z4–8.
Tutti Fritti Mix, possibly superior to Russell hybrids, has large robust flower spikes in a range of bicolors. 3–3.25 ft.
Caryophyllaceae
campion, catchfly
This genus of about 20 species is closely related to Silene and Agrostemma, but over the years there has been considerable nomenclatural confusion. Nonetheless these usually short-lived perennials provide plenty of color, and are easy to grow.
Campions grow best in sun or partly sunny spots where soil is average to moderately fertile. Drainage must be excellent for gray-leaved species but otherwise a dressing of moisture-retaining compost is appreciated. Deadhead to extend bloom time. Erect and sticky, branched stems bear pairs of clammy leaves at swollen nodes. The funnel- or star-shaped flowers have five brightly colored petals, centered with five styles, and followed by five-toothed seed capsules. These are major points of difference from Silene. Cut stems halfway back after blooming to encourage a further crop of flowers. Deadhead to prevent self-seeding.
Lychnis has an interesting history. The name comes from lychnos, the Greek word for “lamp” derived from the usage of furry, felted rose campion (L. coronaria) leaves for lamp wicks. The popular Maltese cross (L. chalcedonica) was grown by Thomas Jefferson at Monticello and was popular among gardeners of the day.
Campions are susceptible to few pests and diseases, except slugs and snails, and resist rabbits and deer. They are larval food and nectar plants for several species of butterflies.
Plant small species to adorn rock gardens and crevice gardens; larger ones are suitable for wild and wildlife gardens, cutting gardens, beds and borders, and between low shrubs.
Start from seed in spring, barely covering them; early seeding may result in bloom the same year. Divide clumps in sprig or fall.
Lychnis alpina
• pink
• spring
• 4–6 in. × 6 in.
• sun, part shade
• Z4–7
Alpine campion, alpine catchfly. Sub-arctic and mountainous areas of the Northern Hemisphere. Low tufts of dark green, lanceolate, 1.5-in. leaves, from which rise short stems topped with clusters of bright pink, 0.75-in. flowers, with frilled, bi-lobed petals. Deadhead to extend bloom time. Appropriate for troughs, rock gardens, and crevices between pavers or flagstones.
Lychnis ×arkwrightii
syn. L. chalcedonica × L. haageana
• orange
• late spring to summer
• 15–18 in. × 12 in.
• sun
• Z5–8
Arkwright’s catchfly. This short-lived hybrid has dark, hairy stems clothed with pairs of maroon-flushed green leaves. The 1.5-in., star-shaped flowers have notched petals, and are arranged in flat-topped clusters.
‘Orange Dwarf’ (‘Orange Zwerg’) has bronzy foliage that contrasts well with the brilliant orange-red flowers. 8–12 in. Z5–8.
‘Vesuvius’ has screaming orange flowers. 18–24 in. Z3–10.
syn. Silene chalcedonica
• scarlet
• summer
• 2–3.5 ft. × 1.5 ft.
• sun
• Z3–10, HS
Maltese cross, Jerusalem cross, scarlet lightning. Native to European regions of Russia, Mongolia, and northwestern China. This old-fashioned cottage garden favorite makes clumps of upright, sticky, unbranched stems that carry pairs of clasping, ovate leaves, toothed along the edges, 2–4 in. long. Dense, terminal, umbel-like heads of flowers composed of numerous star-shaped, orange-red, 0.5- to 1-in. blooms, each with deeply notched petals. Plants are long lived and very hardy, but not in high heat and humidity. Attracts butterflies and hummingbirds. If soil is rich, staking may be necessary; insert twiggy stems (pea sticks) early when shoots are about 6–8 in. Deadhead to discourage self-seeding. Artemisia ‘Powis Castle’ and silvery ornamental grasses make good companions. Mass among shrubs or in deep borders, or group in beds. Good cut flower.
‘Alba’ has pure white flowers.
‘Alba Plena’ has double, white flowers.
‘Dusky Salmon’ has light salmon-pink blooms. Possibly a synonym for ‘Carnea’ and ‘Morgenrot’.
‘Flore Plena’ has double, scarlet flowers. May be brighter than the species, and the double flowers pack more punch.
Lychnis coronaria
syn. Agrostemma coronaria
• cerise
• late spring to early summer
• 1.5–2.5 ft. × 1.5 ft.
• sun, part shade
• Z3–9
Rose campion, mullein pink, dusty miller. Native to southeastern Europe, this easy and showy perennial makes spreading mats of woolly, silvery leaves. These are about 4 in. long, ovate, on short petioles; opposite stem leaves are smaller. Branched stems are topped with solitary, wheel-shaped, cerise flowers, about 1 in. across. Short lived but self-seeds freely; deadhead routinely. Demands very good drainage; root rot may result from poor drainage. Drought tolerant, and suitable for dry gardens, as well as beds, borders, and wildlife gardens. Sometimes used for edging.
‘Abbotswood Rose’ has 2-in.-wide, electric pink flowers over woolly, silver-gray foliage.
‘Alba’ is white flowered.
‘Atrosanguinea’ (‘Bloody William’) has gaudy purplish scarlet flowers above silver foliage mats. More or less sterile resulting in lack of seeds.
‘Gardener’s World’ (‘Blych’, syn. Coronaria tomentosa) has fully double, 1.5-in., deep red flowers. Sterile, thus does not seed about. Long blooming. 2 ft. tall.
‘Oculata’ has white flowers centered with a spreading fuchsia eye. Z4–9.
Lychnis flos-cuculi
• pink, white
• late spring to early summer
• 12–24 in. × 12 in.
• sun, part shade
• Z3–7
Ragged robin. Damp meadows of Europe, Caucasus, Russia. Low mats of grassy, bluish green, basal foliage. Loose, branched, umbel-like clusters of star-shaped magenta or sometimes white flowers. These are 1.5 in. across and shaggy looking, with double, deeply notched petals. Attracts pollinating butterflies and bees. Drought tolerant. Deadhead to curtail self-seeding.
‘Alba’ produces white flowers in early summer. 12–15 in.
‘Jenny’ (‘Nana’) is double flowered with shaggy, pale lavender-pink blooms. Good for rock gardens, front of the border, for cutting, and in containers. 8–12 in. tall.
Lychnis flos-cuculi ‘Jenny’
Lychnis viscaria
syn. Viscaria vulgaris
• magenta
• early to midsummer
• 12–18 in. × 14–16 in.
• sun, part shade
• Z3–7
German catchfly, sticky catchfly. Sandy meadows and dry clearings and roadsides from Europe to western Asia. Evergreen tufts of broadly oblong basal leaves, 3 in. long and without hairs. Stems sticky with glandular hairs rise above the foliage, and bear slender spike-like clusters of three to five bright magenta flowers with notched petals, about 0.75 in. across. Drought tolerant. Long blooming; attracts butterflies and hummingbirds. Self-seeds. Suitable for lining paths, for rock gardens, or as a groundcover; also good for cutting.
‘Alba’ (White Cockle) has white flowers.
‘Fire’ (‘Feuer’) has orange-pink flowers, some double. Protect from intense sun. 18 in. Z3–8.
Passion (‘Splendens Plena’, ‘Flore-Plena’) has double, hot-pink flowers.
Araceae
skunk cabbage, swamp lantern
These remarkable plants deserve a more flattering common name; if they had one they’d undoubtedly play a larger role in our gardens. Lysichitons are botanically distinct from the skunk cabbage found in eastern North American wetlands (Symplocarpus foetidus), although their flowers share the bold foliage and fetid odor of that plant; the aroma attracts pollinating flies and beetles.
Lysichiton blooms resemble those of related Jack-in-the-pulpit, and consist of a central spadix, a finger-like upright stem covered with tiny flowers, partially enclosed by a spathe, or hooded bract. Both species require humus-rich, continually moist soils, and suffer no serious pest problems (including deer), except slugs. They fit well in bog gardens or planted along the margin of ponds or streams; excellent choices for rain gardens.
Propagate by seed direct sown in summer or fall, or moist-chilled and started indoors in early spring. Remove and replant small offsets from mature plants in summer. Naturalizes over time on hospitable sites.
Lysichiton americanus
• yellow
• late winter to early spring
• 1–3 ft. × 3–4 ft.
• sun, part shade
• Z4–7
Western skunk cabbage, western swamp lantern. Native to the Pacific Coast from California to Alaska, and inland through Idaho, Montana, and Wyoming. Long, thick rhizomes support leaves that may measure 4.5 ft. long and almost 3 ft. across. A yellowish green spadix is almost ensheathed by a 5-in., yellow spathe. One of spring’s earliest bloomers.
Lysichiton camtschatcensis
• green, white, yellow
• early spring
• 2–3 ft. high and wide
• sun, part shade
• Z5–7
Skunk cabbage. Northeastern Asia. Before the leaves appear, flowers emerge consisting of a 12-in.-long, yellow to green spadix whose tip may extend beyond the sheath-like, white spathe. Leaves, glossy green and leathery, broadly oval to 3 ft. long, are borne in loose rosettes above rhizomatous roots. Foliage declines in summer heat. Tolerates fairly dense shade, seasonal flooding.
Lysichiton camtschatcensis
Primulaceae
loosestrife
Notwithstanding its common name, this genus is not related to the infamous purple loosestrife (Lythrum salicaria) that has overrun tens of thousands of acres of North America.
Lysimachia grows mainly in damp soil, where its rhizomes can spread widely and sometimes too aggressively. Stems are usually erect with opposite pairs, or whorls of lanceolate leaves, often hairy and sometimes edged with teeth or scallops. The small white or yellow flowers are saucer or star shaped, arranged in terminal spikes or panicles, or solitary in the upper leaf axils.
This genus of about 150 species is easy to grow, especially in moisture-retentive soil amended with compost. Do not allow the plants to dry out during the summer months; browning and crisping of the leaves may result. Although most enjoy full sun, provide shade for variegated plants where midday sun is intense.
Plant larger species in perennial or mixed borders, beside ponds, lakes, and streams, or let them naturalize in light woodlands, or wild gardens. Lysimachias are seldom browsed by deer and reputedly resistant to rabbits. Rust and leaf spots may mar the foliage.
Propagate by seed or divide clumps in spring or fall.
Lysimachia ciliata
syn. Steironema cilicum
• yellow
• early to late summer
• 3–3.5 ft. × 2 ft.
• sun, part shade
• Z5–8
Fringed loosestrife. Native to moist woods and along streams and pond banks in much of southern Canada and the northern United States. Vigorous, rhizomatous perennial with upright, hairy stems clothed with pairs or whorls of lanceolate, hairy leaves, to 6 in. long. Nodding, 1-in., saucer-shaped, yellow flowers, accented with red eyes, are held singly or in pairs on slender stems from the upper leaf axils. Quite invasive; may be difficult to eradicate.
‘Firecracker’ has rich wine-red foliage; yellow flowers. 30–36 in. Z2–9.
‘Purpurea’ has purplish foliage. 24 in.
Lysimachia clethroides
• white
• mid- to late summer
• 2–3 ft. × 3 ft.
• sun, part shade
• Z4–9, HS
Gooseneck loosestrife. China, Japan, Korea. This aggressive exotic spreads by roaming rhizomes and rapidly covers several feet. Contain it in a large sunken trashcan or drainage pipe to stop being overrun. That said, it is excellent as a tall groundcover especially in damp soil, and for cut flowers too. Erect stems bear alternate, narrowly lance-shaped, pointed, 5-in. leaves; mid-green with pale green undersides that turn reddish in fall. Masses of starry, 0.5-in., white flowers are packed into tapering spikes to 8 in. in length; the tips droop in the bud, and regain their upright habit as bloom commences, often leaving the flowers with a “gooseneck” or “crookneck.” Attractive in wildlife gardens where butterflies harvest nectar from the flowers.
‘Geisha’. The foliage of this cultivar has undulating, creamy-yellow edges. Reputed to be less aggressive, and thus better behaved than the species.
Lysimachia congestiflora
syn. L. procumbens
• yellow
• spring to late summer
• 4–6 in. × 12 in.
• sun, part shade
• Z6–9
Dense-flowered loosestrife, creeping Jenny, golden globes. China. Short lived; often grown as an annual. Forms low mats of 2-in., ovate to lance-shaped leaves, arranged in whorls or pairs. Cup-shaped flowers are bright yellow, and 0.75 in. across; they gather in congested terminal clusters. Best in full sun in cool-summer climes, but prefers midday shade in warmer regions. Lovely in summer hanging baskets, window boxes, and containers; colorful as a groundcover or at the front of the border. Non-invasive.
‘Eco Dark Satin’ sports red-throated, yellow flowers, above a deep olive foliage mat. Introduced by Dr. Don Jacobs of Eco Gardens. Best in light shade.
‘Outback Sunset’ (‘Walkabout Sunset’) has gray-green leaves irregularly variegated with yellow; yellow flowers. Demands constant moisture. 2–10 in.
Lysimachia ephemerum
• white
• mid- to late summer
• 3–4 ft. × 1.5 ft.
• sun, part shade
• Z5–9, HS
Milky loosestrife, silver loosestrife, willow-leaved loosestrife. Southwestern Europe, from Portugal west to southern France. Bushy clumps of upright stems with pairs of glaucous grey, lance-shaped leaves, 4–6 in. long, joined at their bases. Dense tapering spires of pearl-like, 0.5-in., white flowers that attract butterflies. Excellent for cutting, beside lakes and ponds, in containers and borders. Non-invasive and elegant; lovely with Japanese iris and swamp rose mallow. This fine perennial deserves a wider audience among gardeners, except in hot and humid regions where the plant will suffer.
Lysimachia ephemerum
Lysimachia nummularia
• yellow
• late spring to late summer
• 2–4 in. × 15–20 in.
• part shade, shade
• Z2–9
Creeping Jenny, creeping Charlie, moneywort. Europe and western Asia. Semi-evergreen in mild climates, this vigorous creeping plant roots at the nodes along its spreading stems. Low mats of rounded, 0.75-in. leaves; solitary, cup-shaped, upward-facing, bright yellow flowers. Grown for its foliage, and largely replaced by the golden-leaved cultivar ‘Aurea’. ‘Goldilocks’, from Proven Winners, and ‘Goldie’ may be identical.
‘Aurea’. Slightly glossy, bright golden leaves light up the garden. Excellent spilling from containers and window boxes, as a groundcover, and along paths. Prefers a slightly sunnier spot than the species. Can become invasive. Z3–10.
Lysimachia punctata
• yellow
• mid-late summer
• 2–3 ft. × 1–2 ft.
• sun, part shade
• Z4–8
Circle flower, yellow loosestrife, whorled loosestrife. Central and southern Europe, but naturalized in many parts of North America. Another species, quick-spreading by rhizomes particularly where soil is damp. Plant beside ponds and lakes, or in wild gardens, with astilbes, Japanese iris, and Joe-Pye weed; very attractive with calla lilies in mild climates. Upright stems with whorls of dark elliptic leaves, 1–3 in. long. Showy, cup-shaped, yellow, 1-in. flowers, red-brown at the throat, cluster in axial whorls on short stems. Increase by seed or take cuttings; may become invasive. Best in cooler climates.
‘Alexander’ has gray-green leaves, edged with white. Yellow flowers.
Golden Alexander (‘Walgodalex’) has lime-green leaves edged with deep cream. Flowers as the species. Not quite as invasive; more compact to 24 in. tall.
Lythraceae
loosestrife
One member of this genus, the dreaded purple loosetrife (Lythrum salicaria), has proven to be a particularly pernicious invasive species. A native of Eurasia, it has naturalized throughout North America outside of Florida to overrun and destroy native habitats in countless acres of wetlands across the continent. Although it is banned in many states, gardeners and nurseries have been reluctant to abandon this perennial, cultivating supposedly “sterile named cultivars” such as ‘Morden Pink’ that produce fertile pollen. These interbreed naturally with the wild-type purple loosestrife within 500 miles, becoming prolific seed producers. Check with your local Cooperative Extension office before buying plants. As an alternative, you could instead plant the native loosestrife, L. alatum, that offers a harmless, even beneficial, alternative.
Lythrum alatum
• pink, purple
• late spring to late summer
• 2–3 ft. × 15–18 in.
• sun
• Z3–8
Winged loosestrife. Native from US East Coast to Montana, Colorado, and Texas, in fields, wet meadows, ditches, and along ponds and streams. Requires a consistently moist soil, and tolerates wet ones. Opposite pairs of lanceolate, sessile leaves are borne on square stems, which have slight wings along the corners. The 0.5-in., six-lobed, flared, rose-lavender flowers are borne singly or paired in the axils of the leaves at the stem tips. Foliage turns orange-red in late summer. Attracts bees, butterflies, and hummingbirds.
Papaveraceae
plume poppy, tree celandine
Two species of plume poppies, Macleaya cordata and M. microcarpa, are commonly found in gardens. They are so similar in appearance that even nurseries that grow them may mislabel them. For gardeners, what matters is the outsized presence plume poppies furnish to any landscape. Here they are lumped together for convenience.
These rhizomatous plants are aggressive in their spread—M. microcarpa is supposedly more troublesome in this respect. Allow plume poppies plenty of room or be prepared to prune back the tough rootstock annually. Macleayas grow best in fertile, moist but well-drained soils. An elegant and imposing choice for the back of borders, they are dramatic behind finer-foliaged, more delicate perennials; the unassertive coloration of plume poppies complements any floral neighbors. Combine with flamboyant sunflowers, cannas, and larger ornamental grasses to create an exuberant, supersized display that makes visitors feel like tourists in a land of giants.
Divide in spring or fall. Take root cuttings during winter dormancy.
Macleaya cordata and M. microcarpa
syn. Bocconia spp.
• white
• summer
• 5–8 ft. × 2–4 ft.
• sun, part shade
• Z3–8
Plume poppy. China, Japan. The species are distinguished chiefly by their stamen number: Macleaya cordata has 24 to 30 stamens per bloom, M. microcarpa has 8 to 12. Tiny, petal-less, creamy-white to pink-tinged flowers, borne in plume-like panicles in summertime. Plume poppies are grassland plants that stand head high when mature, forming groups of stout stems. Handsome broad, grayish to olive-green, lobed stem leaves to 8 in. long, downy with hairs beneath; large plumes of tiny, creamy-white or pink-tinged flowers top the stems.
M. microcarpa ‘Spetchley Ruby’ has blue-green foliage. Reddish flowers followed by red seedheads.
M. microcarpa ‘Kelway’s Coral Plume’ has copper-pink flowers.
Liliaceae
Canada mayflower, false lily-of-the-valley, false Solomon’s seal
This cherished native has acquired numerous interesting common names over the centuries, including elf feather, deerberry, beadruby, and May lily, attesting to its various characteristics. Botanical classification is confusing and in a state of flux; some authorities put it in the Convallariaceae or Asparagaceae.
Not fussy about soil conditions, Canada mayflower is adaptable. Ideally, provide humus-rich, moist soil, with a neutral or slightly acid pH. Best under the partial or even full shade of trees that keep the roots cool and protected from intense sun. Soil must not be allowed to dry out. Best bloom in cooler regions.
Regardless of the alternate common name deerberry, deer apparently ignore the plants; rabbits also ignore these native gems. Plant with Christmas and lady ferns for beautiful woodland displays. Appropriate for wild and wildlife gardens, and damp woodlands.
Propagate by dividing rhizomes in spring; sow seed in containers, but slow to attain bloom size.
Maianthemum canadense
• white
• late spring
• 3–6 in. × 16–9 in.
• part shade, shade
• Z3–7
Canada mayflower. Native in woodlands of southern Canada and northern United States, east to Maine and south to Georgia. A tangle of rhizomatous roots forms large colonies over time under favorable conditions. In spring a single, deciduous, heart-shaped leaf emerges, followed by a separate zigzag flowering stem bearing one to three glossy leaves like mini lily-of-the-valley. Tiny, white starry flowers crowd ten or more into terminal racemes; pollinated by bees and flies. Pea-sized, light pink berries, each with several seeds follow; mice, chipmunks, and often ants consume them. Summer dormant.
Maianthemum canadense
Maianthemum racemosum
syn. Smilacina racemosa
• white
• mid- to late spring
• 2–3 ft. × 1.5–2 ft.
• part shade Z3–8, HS
False Solomon’s seal. Rich woods throughout North America. Clump forming, spreads by rhizomes. Ovate, pointed, medium green leaves with prominent, parallel veins borne alternately along arching, zigzag stems. Fragrant, small, starry flowers are creamy white arranged in plume-like, terminal clusters, followed by green berries that turn red in summer. Yellow fall foliage. May form extensive colonies but resents transplanting once established. Good for woodland gardens, shady borders, and pond sides. No serious pests or diseases. Familiar to many as Smilacina racemosa but recently moved to this genus.
Maianthemum stellatum, starry false Solomon’s seal, is similar but smaller, with 8- to 10-in. stems. Z3–7.
Malvaceae
mallow
In French “mauve” means mallow and in fact the flowers of many mallows are a soft lilac-lavender hue. This genus includes three species of perennials of special interest to gardeners.
All have alternate, palmately lobed leaves and bear five-petaled flowers in pinks or white as well as mauve. The blooms bear a strong family resemblance to those of related hollyhocks and hibiscus, and bloom over a long period. Although perhaps not as refined as tall, slender hollyhocks they are less trouble prone.
Moderately moist, well-drained soils are ideal; mallows are somewhat drought tolerant. Japanese beetles and hollyhock rust attack the foliage, but mallows seldom suffer serious damage, except in very hot, humid summers. Attracts butterflies; rarely browsed by deer.
Often short lived, mallows commonly reseed. Deadhead to encourage rebloom unless saving seed.
Propagate by seed or divide in spring.
Malva alcea
• pink
• summer to early fall
• 2–4 ft. × 1.5–2 ft.
• sun, part shade
• Z4–7, HS
Greater musk-mallow, hollyhock mallow. Native to southwestern, central, and eastern Europe, and southwestern Asia; naturalized in northeastern North America. Hairy stems bear palmately lobed leaves 0.75–3 in. long and wide; basal leaves are shallowly lobed, those on the upper stems are deeply divided and fingered. Flattened clusters of flowers emerge from the upper leaf axils and stem tips; each is bright pink, 1.3–2.3 in. across; no fragrance. To control height, cut back stems in spring. Good for borders and cottage gardens.
‘Fastigiata’ (var. fastigiata) grows upright, with a narrow form. 12–18 in. wide.
Malva sylvestris
Malva sylvestris
syn. M. mauritiana, M. sylvestris var. mauritiana
• mauve-and-purple
• midsummer to early fall
• 3–4 ft. × 1.5–2 ft.
• sun, part shade
• Z5–8
Tall mallow, French hollyhock. Fields and hedgerows of western Europe, northern Africa, and Asia. Erect or decumbent branching stems carry coarse, hairy, maple-like leaves with five to seven shallow lobes; foliage is deep green when young but fades and becomes ragged as the season advances. Bright mauve, 1- to 2.5-in. flowers, striped with darker purple, have notched petals. Short lived but reseeds vigorously. Tolerates heat and humidity better than most mallows or hollyhocks; good for muggy climates.
‘Braveheart’ has dark purple–veined, deep rose flowers.
‘Primley Blue’ grows to 18–24 in., with powder blue, violet-veined flowers.
‘Purple Satin’. Ruffled, burgundy-violet flowers with deeper purple veins.
‘Zebrina’ has satiny, mauve flowers striped with dark maroon.
Malvaceae
turk’s cap mallow
The brilliant red, turban-shaped blossoms borne by turk’s cap mallows would have roused the envy of any old-time Ottoman dandy. Especially decorative in sultry regions, turk’s cap mallows bloom through heat and humidity, and serve as magnets for hummingbirds and butterflies.
Tall turk’s cap mallows are woody at the base with substantial, somewhat coarse, semi-evergreen to evergreen foliage. All tolerate shade and make fine additions to woodland gardens, where they cohabit comfortably with lyreleaf sage, holly fern, and wood fern. Turk’s caps are appropriate for informal borders or naturalized areas. Mostly trouble free, but susceptible to white flies, spider mites, mealybugs, and powdery mildew. Deer resistant.
Propagate by seed, division, or softwood cuttings.
Malvaviscus arboreus
• red
• late spring to midfall
• 4–10 ft. × 4–8 ft.
• sun, part shade
• Z8–11
Turk’s cap. Native to subtropical Texas and cloud forests of Mexico and Colombia. A coarse expansive shrubby perennial with branching stems, woody at the base; three-lobed, broadly oval to heart-shaped leaves to 5 in. or more long, dark green above, paler with down beneath. Bright red, 1-in.-long flowers never open; petals remain tightly spiraled with a long pistil and protruding stamens. Red fruits are five-lobed capsules, a popular food for wildlife. Vigorous and adaptable. Cut back stem tips periodically to encourage branching and bloom.
Malvaviscus drummondii
syn. M. arboreus var. drummondii
• reddish orange
• late summer to late fall
• 5 ft. high and wide
• sun, part shade
• Z8–10
Turk’s cap. Texas coastal plain east to Florida and West Indies, Cuba, and Mexico. Evergreen in the southern part of its range, but herbaceous further north; survives in zone 7 with winter protection. Upright or somewhat reclining stems bear 4- to 6-in., hairy, dull green leaves. Vermilion-red spiraling flowers are twisted into a tube showing exserted red stamens.
‘Big Momma’ has flowers a third larger than the species. Introduced by Texas horticulturist Greg Grant.
‘White Lightning’ has white flowers.
Malvaviscus drummondii
Other Notable Cultivars
‘Pam Puryear’ (Malvaviscus drummondii × M. arboreus) has peachy pink flowers. A Greg Grant introduction, named for the noted Texas Rose Rustler. 5 ft. high and wide. Z7 with protection.
Lamiaceae
horehound
Best known as a flavoring for cough drops, common horehound (or hoarhound), Marrubium vulgare has been used medicinally for centuries. While that species is not valuable outside herb gardens, its relative M. incana earns space in beds and borders with its woolly, silver-gray foliage. This provides a cooling foil for colorful companions, such as rudbeckias, veronicas, and even roses. Lovely with ornamental forms of other Mediterranean herbs: lavenders, oreganos, thymes, and sages.
Mint-like rhizomes can become invasive, especially in fertile soil conditions. Provide poor, free-draining soil to keep under control. Drought tolerant; pest and disease free, including deer.
Divide clumps in spring or fall, or take summer cuttings.
Marrubium cylleneum
• lavender
• midsummer
• 4–12 in. × 24 in.
• sun, part shade
• Z8–10
Horehound. Greece, Albania. Upright, square, woolly stems carry opposite pairs of sage-green leaves, textured and soft, rimmed with white, undulating edges. Vertillasters of lavender-pink, two-lipped flowers crowd the leaf axils. Very tolerant of drought; thrives in hot, dry climates.
Marrubium cylleneum
Marrubium incanum
syn. M. candidissimum of gardens
• white
• early summer
• 1–3 ft. × 2 ft.
• sun
• Z3–10
Woolly horehound, silver horehound. Italy, Sicily, Balkans. This silky-haired, woolly perennial presents the effect of hoar frost on the foliage. Bushy and erect, the square stems are clothed with pairs of crinkled, sage-like, 1- to 2-in. leaves, rimmed with small teeth, white-felted beneath. Insignificant white, two-lipped flowers cluster in whorls at the nodes. Prune routinely to encourage bushy growth.
Asteraceae
Barbara’s buttons
Endangered in several areas where its favored moist riverbanks and open woods have been destroyed, this seldom-cultivated but attractive native is perfect for native plant and wild gardens; good for cutting. Partner with other damp-loving natives including beebalm, cardinal flower, and turtlehead.
Best in sun in damp soil abundantly enriched with organic matter. Seldom browsed by deer or rabbits, or attacked by pests and diseases. Attracts butterflies and birds.
Propagate by seed or divide established plants.
Marshallia grandiflora
• pink
• early to midsummer
• 1–2 ft. × 1 ft.
• sun, part shade
• Z5–9
Giant Barbara’s buttons, Appalachian Barbara’s buttons. Central Appalachia and eastern United States. Easy-to-grow clumps of glossy, evergreen, lanceolate leaves to 7 in. long. Solitary, 1.25-in., pinwheel-like heads of tubular mauve or pinkish florets with bluish purple anthers top 18- to 24-in. stalks. Plants seed themselves gently.
Phrymaceae
creeping mazus
Formerly classified with snapdragons in the Scrophulariaceae, Mazus is now placed in the Phrymaceae with monkey flower. Just a single species is garden worthy. Creeping mazus is excellent as a groundcover. Tolerant of light foot traffic and occasional mowing, it is easy care and requires little maintenance. Evergreen in mild climates. It thrives growing in crevices between pavers on patios and pathways, in rock gardens, and is lovely underplanting weigelas, bush cinquefoils, and viburnums, and as a skirt for spring bulbs. It can be allowed to naturalize and does well in rain gardens.
Plant creeping mazus in sun or partly shaded spots in moisture-retentive soil amended with organic matter; if kept moist it tolerates summer heat and humidity but should not dry out excessively in summer. Seldom browsed by deer or rabbits, this charmer is more or less pest and disease free.
Propagate by division in spring or start from seed.
Mazus reptans
• purple blue
• late spring to early summer
• 2–4 in. × 24 in.
• sun, part shade
• Z5–8
Creeping mazus. Himalayan region. Prostrate, with tight, dense mats of bright green, more or less elliptic, coarsely toothed, 0.5- to 1-in. leaves. Abundant few-flowered clusters of small, five-petaled, lavender-mauve flowers blanket the foliage; these are two-lipped, the lower blotched with white, subtly dotted with red. Spreads by runners that root at the nodes. May invade lawns.
‘Albus’ (‘Alba’) has clean white flowers
Mazus reptans ‘Albus’
Papaveraceae
Himalayan poppy
A geographical puzzle, this genus includes one species native to the British Isles and almost 40 more indigenous to the Himalayas. These poppy relatives, annuals, biennials, and evergreen or herbaceous perennials all prefer cool, moist climates and seldom flourish in regions with hot, humid summers. Typically they form rosettes of hairy leaves and four-petaled, bowl-shaped flowers, reminiscent of related poppies.
Best where summers are cool, with moisture-retentive, well-drained, acid soil; they rot out in winter with wet feet. Organic mulch helps to maintain consistent soil moisture. The strong taproots resent disturbance.
All make fine additions to cottage gardens, wildflower meadows, or rock gardens; the blue poppies, for those who master their cultivation, also provide a choice ornament for sunny, well-drained borders and containers. Prone to attack by slugs and snails; deer resistant.
Propagate by fresh seed.
Meconopsis betonicifolia
• blue
• late spring to early summer
• 24–48 in. × 18–24 in.
• part shade
• Z7–8, HS
Blue poppy. Himalayas. Basal rosette of 6-in., toothed leaves covered with rusty hairs; 2- to 3-in.-wide, sky-blue flowers borne singly or in terminal cymes. Not difficult to grow in suitable climates. If soil is not sufficiently acid, colors may be muddy mauve instead. A border and rock garden gem.
‘Hensol Violet’ has lilac-rose flowers.
Meconopsis cambrica
• yellow, orange
• late spring to early summer
• 18 in. × 12 in.
• sun, part shade
• Z5–9, HS
Welsh poppy. Britain, Ireland, western part of northern Europe. The easiest to cultivate, this species produces basal rosettes of divided, deeply toothed, pale green leaves, from which rise upright, bristly stems that carry solitary, 2- to 3-in., bowl-shaped, yellow to orange blooms; occasionally reblooms after initial flush of flowers. Plants are short lived but reseed prolifically, even sometimes becoming invasive. Particularly attractive naturalized in open woodland settings with Virginia bluebells, forget-me-nots, or grape hyacinths. Fresh seed is essential.
‘Flore Pleno’ bears double, yellow flowers.
‘Muriel Brown’ bears double, orange-red flowers.
‘Rubra’ has single, red flowers, 3 in. in diameter.
Meconopsis grandis
• blue
• late spring to early summer
• 2–4 ft. × 1–2 ft.
• part shade
• Z5–7, HS
Blue poppy, Asiatic poppy. Western Himalayas, northern Burma, Tibet, and Yunnan. Basal rosettes composed of bristly, entire or coarsely toothed, wedge-shaped, medium green leaves, to 12 in. long. Upright stems bear cupped, deep sky-blue flowers, 4–5 in. across. Requires climate and soil similar to those favored by Meconopsis betonicifolia: best adapted to mild coastal regions, or higher altitudes of mountain states. Appropriate for open woodlands or rock gardens. A heartbreaker, but a triumph for those who bring this treasure to bloom.
Other Notable Cultivars
×sheldonii ‘Lingholm’ (Meconopsis betonicifolia × M. grandis). Bristly, 6- to 10-in. leaves, rich blue, 1.25-in. flowers from late spring. Treat as M. betonicifolia or M. grandis; hybrid vigor reputedly makes ‘Lingholm’ easier to cultivate. 48 in. × 18 in. Z3–7.
‘Slieve Donard’ is vigorous with pointed, rich blue flowers. To 36 in.
Lamiaceae
mint
Despite their seductive appeal to eye, nose, and tongue, most of the mints are simply too invasive to be released in perennial gardens. A few less-aggressive types, however, can fill the need for a self-sufficient, fast-growing groundcover, an aromatic filler for hanging baskets and containers, or even low-growing herbage to tuck into the cracks of a sunny flagstone terrace.
As a group, mints are characterized by expansive underground and aboveground stolons, erect square stems, opposite oblong to lanceolate, aromatic leaves, and small, two-lipped flowers borne in tiered whorls or verticillasters of blossoms at the upper nodes. Deer ignore them.
Mints flourish on rich, moist but well-drained soils in full sun or part shade. When grown on wet and/or excessively rich soils they are fall prey to fungal diseases. In intense sun, variegated cultivars may burn; they are somewhat less vigorous (an advantage in the case of mints). Plant mints in pots or tile drains buried almost to their rims to restrain their roving roots temporarily. Cut back top growth regularly to encourage bushy, compact new growth. Mints attract bees, butterflies, and pollinating insects but resist deer and rabbits.
Propagate cultivars by division, as mints hybridize readily, or by stem cuttings.
Mentha requienii
• purple
• midsummer
• 1 in. × 6–12 in.
• part shade
• Z7–9
Corsican mint. Corsica, Sardinia, France, and mainland Italy. Produces a carpet of tiny, bright green leaves with crème de menthe fragrance, and tiny, mauve flowers. Tolerates light foot traffic, suitable for planting in cracks between paving stones, or around the base of taller plants in a container.
Mentha spicata ‘Crispa’
• pink-purple
• midsummer to early fall
• 1–2 ft. high and wide
• sun, part shade
• Z4–10
Curly mint. A spearmint selection of horticultural origin. Bright green leaves, highly curled along their edges, with a strong spearmint fragrance; dense spikes of pale-lilac flowers in summer. Just as invasive, curly mint is smaller than regular spearmint.
Mentha suaveolens ‘Variegata’
syn. M. rotundifolia ‘Variegata’
• cream
• summer
• 24 in. × 24–36 in.
• sun, part shade
• Z5–10
Pineapple mint. Southern and western Europe. Variegated cream-and-green leaves with a light fragrance of pineapple, scalloped edges, and crinkled texture.
Boraginaceae
bluebells
Blues lovers will find much to enjoy in this genus of some 50 species, 18 of which are North American natives. These herbaceous perennials vary from small alpine gems to 3-ft.-tall woodlanders. They are adapted to a remarkable range of habitats; some retreat underground and become summer dormant. The flowers, borne in nodding clusters, are typically bell shaped, and range from pale to dark violet-blues, some even open blue but mature to pink. Bluebells are available for almost any site.
Propagate by seed sown in fall; overwinter with protection. Divide mature specimens in spring, or take root cuttings in early autumn.
Mertensia ciliata
• blue
• early to midsummer
• 0.5–4 ft. high and wide
• sun
• Z4–9
Tall fringed bluebells. Native to subalpine meadows and streamsides in the United States, from the Rockies to the Pacific Coast. Groups of stems arise from branched, woody bases, and bear fleshy, blue-green, alternate, ovate to elliptic leaves, to 6 in. long, that narrow as they ascend the stems. Branched, open clusters of nodding, fragrant, tubular flowers to 0.75 in. long that flare at the mouths. Drought tolerant; a well-drained, moist, and peaty soil is ideal. In the wild they mass in mountain meadows; excellent to naturalize in gardens of the western United States.
Mertensia maritima
• blue, pink
• late spring to early summer
• 2–4 in. × 8–12 in.
• sun
• Z4–8
Oysterleaf. Beaches of northern North America, northeastern Asia, and northwestern Europe. Attractive, low mounds of blue-green, ovate leaves. Flowers cluster at stems tips; pink in the bud opening to blue. Provide a neutral to slightly alkaline, well-drained soil of average fertility and moisture. Leaves reportedly taste like oysters. Handsome in containers, rock gardens, or seaside plantings.
Mertensia virginica
syn. M. pulmonariodes, Pulmonaria virginica
• blue
• early spring
• 1.5–2 ft. × 1–1.5 ft.
• part shade, shade
• Z3–8
Virginia bluebells. Moist woods and river bottoms from New York and southern Ontario to eastern Minnesota, south to Kansas, Arkansas, and North Carolina. Clumps of erect stems carry smooth, oval, bluish green leaves to 4 in. long. Pendulous, trumpet-shaped, 1-in.-long flowers cluster in loose, terminal clusters; buds are pink and young flowers pinkish blue, maturing to sky blue. This popular native spring ephemeral yellows and becomes dormant as summer heat arrives. Prefers moist, rich soils, but tolerates average garden soil with irrigation. Naturalize in woodland and wildflower gardens.
Mertensia virginica
Phrymaceae
monkey flower, musk flower
Unlike so many other perennials that demand a well-drained soil, monkey flowers thrive in damp places, especially in regions with a warm climate. Their showy snapdragon-like flowers arise from the leaf axils or gather into terminal racemes at stem tips. They appear like a gaping mouth with a two-lobed, sometimes reflexed, upper lip and a pendulous, three-lobed lower one; an open throat between them is sometimes protected by a palate. The floral hues include almost everything except blue, the lower lip often decorated with contrasting spots. Frequently toothed, the stem leaves are arranged in opposite pairs.
Monkey flowers thrive in damp, fertile soils copiously amended with organic matter; some species prefer to grow in shallow water. Sunny positions are best, but they tolerate light or dappled shade, especially in hot areas. Where winters are overly harsh, monkey flowers are frequently grown as summer annuals. Keep well watered and fertilize monthly to keep bloom coming. Pests and diseases are seldom serious; tolerates deer and rabbits well.
Ideal for rain gardens, water gardens, streamsides, and bog gardens, monkey flowers also perform well in beds and borders if they are kept moist. Good companions include water iris, ligularias, meadowsweets, and other lovers of damp sites.
Increase mimulus from seed sown in fall or spring, or divide the crowns in spring. Soft cuttings root well in late spring or early summer.
Mimulus cardinalis
• red
• late spring to fall
• 2–3 ft. × 1–2 ft.
• sun, part shade, shade
• Z5–10
Scarlet monkey flower. Mountain regions surrounding deserts of California, the western United States, and Mexico. Clumps of sticky-hairy, rather weak, branched stems bear opposite pairs of evergreen, sessile, 1- to 4-in.-long, obovate, toothed leaves. Conspicuously two-lipped and tubular with exserted stamens, yellow-throated, scarlet or brick-colored, 2-in. flowers are borne on long stems. Their major pollinators, hummingbirds, frequently visit these very showy flowers, as do butterflies. Great for wildlife gardens, wildflower gardens, beside water features. Protect from intense sun. Should not dry out, especially during periods of drought. Cut back in late summer to encourage further bloom. This species sets copious amounts of seed.
‘Santa Cruz Island’ has yellow flowers. Originally collected on Santa Cruz Island.
• orange red
• late spring to summer
• 1–2 ft. × 2 ft.
• sun, part shade
• Z7–10
Flor de cobre. In the wild, this species grows at high altitudes around the timberline in Chile. Freely branching, with mostly hairless stems and conspicuously veined, coarsely toothed, oval leaves to 1.25 in. long. The 1- to 1.5-in. flowers are golden yellow when young, but quickly darken to a screaming orange with red-spotted throats. Demands constant moisture; best sited along waterways, in bog gardens, or swampy spots. Grow as an annual in colder areas.
Mimulus cupreus
Mimulus guttatus
syn. M. langsdorfii
• yellow
• early summer to fall
• 1–2 ft. × 2 ft.
• sun, part shade
• Z6–9
Common monkey flower. Native from California, north to Alaska, this vigorous, erect or spreading, fleshy plant roots at the nodes where stems touch the ground. Broadly oval, petioled, 1- to 6-in. leaves are toothed; upper leaves sessile. The typical 1- to 2-in. monkey flowers are bright yellow, frequently mottled and speckled with red on the lower lobe, and arranged in terminal racemes. This species is a parent of the ×hybridus group.
Mimulus ×hybridus
syn. M. guttatus × M. luteus
• various
• early summer to fall
• 1–2 ft. × 2 ft.
• sun, part shade
• Z9–11
Hybrid mimulus, of garden origin. Except in mild climates, these are mostly grown as summer annuals in containers, and beds and borders. This breeding has spawned several worthy strains including:
Calypso. A mixture in various striking color combinations of red, orange, burgundy, and pink, spotted and blotched, bicolored, or self-colored. 6–10 in.
Magic Mix. Blooms early in shades of red, orange, yellow, cream, and pink. Good for landscapes and containers. 6–8 in. tall.
Malibu Series. Yellow, red, and orange trailing plants, excellent for baskets. 6–8 in.
Mimulus luteus
• yellow
• late spring to summer
• 12 in. × 12–24 in.
• sun, part shade
• Z7–9, HS
Yellow monkey flower, small monkey flower. Chile. Vigorous creeping mats root at the nodes. Oval, 1.5-in. leaves are toothed; pairs of bright yellow, red-spotted, 1.5- to 2-in. flowers adorn the leaf axils. Self-seeds freely. An excellent groundcover; tolerates growing in up to 3 in. of water. A parent of the ×hybridus group.
Mimulus ringens
• purple
• early summer to fall
• 2–3 ft. × 1 ft.
• sun, part shade
• Z4–9
Allegheny monkey flower, square-stemmed monkey flower. Native to wet habitats of eastern and central United States. This smooth, hairless perennial with creeping rhizomes grows upright with watery, ridged, square stems. Lanceolate, toothed, 3- to 4-in. leaves are sessile and often clasp the stem. In the leaf axils, pairs of long-stemmed lavender-purple flowers emerge from ribbed calyces; the larger, lower, lobed lip is speckled with violet and a visible yellow palate closes the throat. Self-seeds freely, and spreads by rhizomes. Ideal for damp borders and waterside sites; tolerates growing in water to 6 in. deep.
Lamiaceae
beebalm, bergamot
Used by indigenous peoples as a treatment for a wide variety of ailments, this genus of North American wildflowers continues to supply the antiseptic, thymol, employed in many modern mouthwashes. Gardeners value these hardy mint relatives for their aromatic foliage and long-lasting bloom. Like the mints, beebalms have square stems and small, tubular flowers borne in dense, mop-headed clusters.
Flourishing on a wide range of soils, beebalms prefer a moderately moist, well-drained site, but tolerate some drought once established. As their common name suggests, their nectar-rich flowers attract bees as well as butterflies and hummingbirds. The more refined hybrid selections hold their own in mixed borders; as a group however beebalms appear more at home in less formal meadows, native plant gardens, and open woods, or alongside ponds and streams. They have the rare ability to grow under black walnut trees. Good companions include black-eyed Susans, coneflowers, Shasta daisies, and gayfeathers. Little troubled by insect pests, deer, or rabbits; beebalms are, however, susceptible to powdery mildew. Search out mildew-resistant selections.
Propagate by seed; take stem cuttings or divide named cultivars in late spring.
Monarda didyma
• red
• early to late summer
• 2–4 ft. × 2–3 ft.
• sun, part shade
• Z4–9
Oswego tea, beebalm. Eastern United States and Canada. Clumps of stems clothed with aromatic, alternate, lanceolate, 3- to 5-in. leaves rimmed with teeth. Dense terminal heads of red flowers top whorls of showy red-tinged, leafy bracts. Shade from intense sun. Unlike other beebalms, this species must not dry out; a good choice for rain gardens.
‘Adam’ has red flowers. More drought tolerant than the species.
‘Croftway Pink’ is a lovely rosy pink. Susceptible to mildew.
‘Grand Parade’ offers lavender-purple flowers. 13–16 in. × 16–20 in. Z3–8.
‘Jacob Cline’ has outstandingly large, brilliant red flowers. Largely mildew resistant.
‘Purple Rooster’ displays large, rich purple flowers. Mildew resistant. 36 in. × 26 in.
Monarda fistulosa
• pink, lavender
• early to late summer
• 2–4 ft. × 2–3 ft.
• sun, part shade
• Z3–9
Wild bergamot. Native to prairies, dry, rocky woods, and woodland margins, and in unplanted fields and along roadsides in United States, Canada, and Mexico. Clump forming with oblong, grayish green leaves to 4 in. long. Two-lipped, lavender flowers cluster in terminal, globular heads above whorls of showy, pinkish bracts. Prefers dry to moderately moist, well-drained soil, but tolerates clay, shallow, rocky soils, and some drought. Reseeds; best for naturalized informal plantings. Prone to powdery mildew.
Monarda punctata
• yellow, purple
• early summer
• 18–24 in. × 9–12 in.
• sun, part shade
• Z3–8
Dotted beebalm, spotted horsemint. Eastern United States. Clump forming with toothed, aromatic, oblong leaves to 3 in. long. Two-lipped, tubular flowers are yellow, spotted with purple. They are borne in upper leaf axils and at stem ends in tiered, stem-encircling clusters supported on whorls of showy, pinkish bracts. Prefers dry to moderately moist, well-drained soil; tolerates poor soils and some drought. Self-seeds.
‘Fantasy’ is an exceptionally robust cultivar. 2–2.5 ft. × 2–3 ft.
Other Notable Cultivars
‘Blue Stocking’ (‘Blaustrumpf’) has deep lilac flowers. Quite heat and drought tolerant. 36–60 in. × 24 in. Z4–10.
‘Colrain Red’ has deep red flowers. Mildew resistant. 3–4 ft. Z4–9.
Monarda ‘Colrain Red’
‘Gardenview Scarlet’ has bright rose-red flowers; mildew resistant. Introduced by Henry Ross, Gardenview Park, Ohio. Has largely replaced mildew-prone ‘Cambridge Scarlet’. 36 in. × 24 in. Z4–10.
‘Marshall’s Delight’. A mildew-resistant Canadian introduction with densely packed heads of showy pink flowers. 36–48 in. × 24–36 in. Z4–9.
‘Pardon My Purple’ is dwarf with 2.5- to 3-in., fuchsia-purple flowers. 12 in. tall
‘Petite Delight’ is dwarf with lavender-pink flowers. Mildew resistant. 12–15 in. × 18–24 in. Z2–8.
syn. Acanthocalyx
Morinaceae (Dipsacaceae)
whorlflower
Few would recognize this thistle lookalike when not in bloom. Its attractive whorls of fragrant flowers borne on spikes on straight-up stems are appealing in summer, but the vicious-looking spines that decorate the leaf edges too often put off gardeners. Leaves are evergreen in mild-winter regions. Neverthless, it deserves a much wider audience.
Somewhat temperamental, whorlflower does best in full sun in highly fertile soil with very good drainage. Tolerant of drought but not of wet feet; usually heavy clay soils that drain poorly mean death. Where this fragrant plant grows well (the crushed leaves have a lemony scent), it certainly earns its place in cottage gardens, beds, and borders, preferably where it will not be in contact with people. Wear gloves to handle, not only for protection against the spines, but also because the sap can cause a rash on sensitive skins.
Propagate by seed outdoors in fall as soon as it ripens; cover very thinly with fine compost. Seedlings take two to three years to reach blooming size. Self-seeds; avoid weeding out the thistle-like seedlings by mistake.
Morina longifolia
• white
• midsummer
• 2–3 ft. × 1–1.5 ft.
• sun, part shade
• Z6–8, HS
Whorlflower, Himalayan whorlflower. Himalayas from Kashmir to Bhutan. The whole plant is covered with wickedly sharp spines, especially the basal rosette of dark green leaves, and the whorls of bracts on the stem that protect the flower clusters. Dagger-shaped, glossy, 10- to 12-in. lower leaves are equipped with stiff spines along undulating margins. Erect flower stems bear tiers or whorls of tubular, 1.25-in., white flowers ringed with spines. The flowers turn rosy pink and then red after they have been fertilized. Reportedly this change in color signals pollinating insects to visit white flowers not yet pollinated. Spent flower stems are attractive as dried flowers.
Saxifragaceae
mapleleaf tickfoil
A recent addition to the perennial plant palette, mapleleaf tickfoil will surely become popular as a weed-suppressing groundcover, especially in shade. Rhizomatous roots produce basal rosettes composed of palmately divided, maple-like leaves. Clusters of small, starry flowers reminiscent of related coral bells rise above.
This beautiful deciduous plant, native to woodlands and rocky slopes of China, Japan, and Korea, is named for Mukden, the ancient capitol of Manchuria, now known as Shenyang. They do best in regions with cool summers, where they enjoy sun or light shade; they must not dry out. If grown in warmer climes, part shade is a must. Amend soil with organic matter to improve drainage yet retain moisture; it must not waterlog. Slugs and snails may devour succulent young growth, but deer and rabbits tend to ignore them.
Mukdenias are grown primarily for their foliage, although the flowers are quite charming. An excellent and unusual plant for Asian-style gardens, for edging beds and borders, woodlands, in rock gardens, or planted close as a groundcover beneath shrubs. Combine with hellebores, coral bells, variegated Hakone grass, and others appreciative of light shade.
Divide established plants in spring before bud break, or sow seed in fall, preferably in containers.
Mukdenia rossii
syn. Aceriphyllum rossi
• white
• midspring
• 8–15 in. × 12–24 in.
• part shade, shade
• Z4–8
Mukdenia. Northeast Asia. Fans of asymmetrically divided, basal foliage emerge with or just after the clusters of pink buds that open to white, starry flowers on leafless, 16-in., pink stems. Each long-stalked toothed leaf is deeply divided into five to eight lobes. The young green leaves, pinkish beneath, increase in size as they mature, reaching 6 in. across, and take on a burnt red cast as the season progresses.
‘Crimson Fans’ (‘Karasuba’) is the most popular cultivar. Its dramatic, lustrous leaves are irregularly bordered with bronze. In response to cooler fall nights and perhaps shorter days, the leaves turn intense crimson burgundy from the edges inward.
Mukdenia rossii
Boraginaceae
forget-me-not
Nothing says nostalgic charm like forget-me-nots, and very few perennials are as easy to grow. If you can provide a moist, organic-rich soil in sun or part shade, forget-me-nots of one kind or another will flourish in your garden from Alaska to zone 8 in the southeastern United States and into zone 9 on the West Coast. These mid- to late spring bloomers display a range of flower colors from the namesake forget-me-not blue to pink and white. The five-lobed flowers are individually small but are borne in natural nosegays, and commonly spread seed to form increasing colonies. Almost mandatory for cottage gardens, forget-me-nots combine well with astilbes, bergenias, coral bells, and primroses in woodland gardens, and are naturals for moist meadows, streambanks, or pondsides. Deer resistant; attracts butterflies.
Propagate by seed or division.
Myosotis asiatica
syn. M. alpestris
• blue
• midspring to midsummer
• 6–12 in. × 4–6 in.
• sun, part shade
• Z3–8, HS
Mountain forget-me-not, Asian forget-me-not. Native to northern regions of the world, including from Alaska through the Pacific Northwest and the Rocky Mountains to Colorado. Commonly sold in the nursery trade as Myosotis alpestris, under which name it serves as the state flower of Alaska. Bloom season varies with the climate, being delayed in northern regions or at high altitudes. Leafless clusters of yellow-eyed, blue flowers to 0.3 in. Leaves oblanceolate to elliptic, to 5 in. long at base, shorter as they ascend the stems. Grows best on well-drained moist to wet soils with neutral pH. Sensitive to combined heat and humidity. Ideal for rock gardens and containers. Susceptible to red spider mites, powdery mildew, and leaf rot, especially where summers are hot.
‘Ultramarine’ produces prolific flushes of intensely deep blue flowers.
Victoria Series offers cultivars with blue, pink, or white flowers.
Myosotis scorpioides
syn. M. palustris
• blue
• late spring to midsummer
• 6–12 in. × 9–12 in.
• sun, part shade
• Z5–9
True forget-me-not, water forget-me-not. Temperate North America. Glossy, oblong to lanceolate, bright green leaves to 4 in. long; yellow-eyed, light sky-blue flowers are 0.25 in. across, borne in scorpioid cymes that uncoil as flowers open (like a scorpion extending his sting). Adapts to growing in shallow water to 3 in. deep; good for margins of water gardens, streams, and ponds, where it covers the ground (not aggressively) by creeping rhizomes. Pinch young growth to encourage bushiness. Insect and disease resistant, with the exception of mildew and rust.
var. semperflorens is dwarf with heavier, longer bloom than the species. Repeat blooms sporadically to frost. 6–8 in.
‘Southern Blues’ grows to only 6 in. but spreads vigorously. Sky-blue flowers. Exceptionally tolerant of sultry summers.
‘Unforgettable’ has variegated, cream-edged foliage; bright blue flowers.
Myosotis sylvatica
• blue, pink
• mid- to late spring
• 6–12 in. × 6–9 in.
• sun, part shade
• Z3–8
Forget-me-not. European native that flourishes as a garden escapee in many parts of North America. Tufts of hairy, green, oblong-lanceolate leaves 1–3 in. long; dense cymes of yellow- or white-eyed, blue flowers, to 0.4 in. in diameter. Short-lived perennial, persists through self-seeding. Provide afternoon shade where summers are hot. Refined enough for borders or beds but also appropriate when naturalized at woodland edges or pond and stream margins. Excellent and traditional interplanting for spring bulb displays, forget-me-not foliage provides cover as bulbs fade into dormancy. Susceptible to mildew and rust.
‘Bluesylva’, part of the Sylva Series, has bright blue flowers and a compact growth habit. 6–8 in. × 12–18 in. The series also includes bright pink, white- or light yellow-eyed ‘Rosylva’, and white, yellow-eyed ‘Snowsylva’. These are especially good for edging.
‘Royal Blue Compact’ has sky-blue flowers, accented with white or yellow eyes. Compact. 6–8 in. × 4–6 in.
Myosotis sylvatica
Apiaceae
sweet Cicely, garden myrrh
This underused herb earns its place both in herb gardens and in borders. The attractive fern-like foliage is bright green and remains attractive throughout the season. Early summer umbels of flowers are similar to Queen Anne’s lace, but since the whole plant is so aromatic they are easy to distinguish.
Sweet Cicely foliage has a light but definite fragrance of anise and is a great addition to fresh-fruit salads, to tart rhubarb and plum pies, and even to meat dishes; the chopped leaves enable less sugar to be used. Ongoing research will determine if sweet Cicely is viable as a sugar substitute for diabetics. The deep roots are also aromatic; sometimes used as a root vegetable. Add seeds ripe or green to add flavor and sweetness to fruit dishes.
Grow sweet Cicely in dappled shade in well-drained, moist, fertile soil. Deadhead to control self-seeding. For best foliage flavor, harvest prior to bloom time.
Start seed in fall in containers for spring planting. Take care not to damage the developing root system.
Myrrhis odorata
• white
• early summer
• 3–4 ft. × 2 ft.
• part shade
• Z3–7
Sweet Cicely, Spanish chervil. Mountains of central Europe. One of the prettiest aromatic herbs in the parsley family, sweet Cicely has stout, ribbed, and hollow stems. These carry delicate ferny leaves, two or three times divided into smaller, toothed leaflets. Small, white flowers arranged in compound umbels top the stems and upper leaf axils. These attract bees, butterflies, and hummingbirds. Persistent seedheads follow; useful in dried arrangements.
Myrrhis odorata
