Sunflower & Rudbeckia

HELIANTHUS & RUDBECKIA

SUNFLOWERS AND RUDBECKIAS ARE AMONG THE LAST TO BLOOM EACH YEAR. THEY ADD WONDERFUL COLOR IN THE GARDEN AND ALONG FENCES AND WALLS, AND MOST VARIETIES MAKE SUPERB CUTTING FLOWERS.

When my little brother George was planning his wedding at Turkey Hill, both he and Rita, his fiancée, wanted colorful garden flowers as the theme. I suggested planting many types of sunflowers as a backdrop for the luncheon reception tent. By late August, the sunflowers were blooming profusely, and everyone was taking photos of the 10- and 12-foot-tall flowers. On the tables, we were able to arrange asters, rudbeckias, a few dahlias and coleus, and the last of the snapdragons; the effect was charming, homey, and old-fashioned—just what the couple wanted.

Our perception of sunflowers has been of long-stemmed, giant heads, full of black seeds and rimmed with bright yellow petals, swaying in the breeze, nodding to the sun. The fields I first drove past in France and Italy many years ago are still clear in my mind. But now sunflowers come in so many different types and colors. They are no longer cultivated just as a source for seeds and oil, but also for the cut-flower market, where variety is key to their long-standing popularity.

The garden can be as interesting and useful in the autumn as at other times of the growing season, thanks to many varieties of sunflowers and rudbeckias, better known as black-eyed Susans. Mixed into perennial or annual gardens and borders, these will flower late into autumn.

Sunflowers now come in miniature varieties, 2 to 4 feet in height, and others can range from 5 to 10 feet, although I have received photographs from friends and customers of our sunflower seeds depicting plants as tall as 20 feet!

Sunflowers demonstrate a particularly robust character, and that is why I like to plant many along sunny fences, and toward the backs of large gardens. Not only are they perfect for cutting, but when left in the garden they can ripen into food for wild birds. Many sunflowers are annuals, but they often leave seeds, which can grow the following year into healthy plants.

Rudbeckias are vibrant herbaceous perennials, blooming midsummer to late fall if pruned and deadheaded. The flowers last for weeks in the garden. Once largely available only in yellow with dark brown centers, rudbeckias now can be found in many shades of yellow, orange, russet, mahogany, and bronze, with petals arranged in single, semi-double, and fully double rows around dark-centered seed heads. The stems and leaves of rudbeckias are rough and woolly.

The offerings of sunflowers and black-eyed Susans on many roadside farm stands in August and September are outstanding. One can find all sorts of types—the giant seed-centric varieties (great for bird feeders); the more easily used ‘Teddy Bear’, ‘Inca Jewels’, and ‘Chocolate’ sunflowers; and the common black-eyed Susan (hirtus) and ‘Cherokee Sunset’ varieties of rudbeckia.

Kevin mixes these flowers en masse and finds that leafy grapevines, grasses, and even Queen Anne’s lace soften and enhance any arrangement of them. I will continue to grow these two types of flowers year after year, and not only will I enjoy the fruits of my labor, but the hungry birds, who are no longer migrating south but hanging around Katonah twelve months a year, will enjoy them even more.

Greens add lightness and movement to a mass of sunflowers (this arrangement includes ‘Autumn Beauty’, ‘Inca Jewels’, ‘Ring of Fire’, and ‘Chocolate’ varieties)in a weighty, antique brass coal shuttle. Kevin used chicken wire to hold the flowers in place. He then added an explosion of grapevines to draw the eye out, and positioned the lighter flowers toward the bottom of the arrangement to create a layered effect.

Although they share the same family, Asteraceae, sunflowers and rudbeckias are distinct in their respective genus and species. Rudbeckias have smaller blossoms, although species like R. laciniata can grow to 9 feet tall. Rudbeckias have many varieties aside from the commonly known black-eyed Susan, as do sunflowers. Here, the ‘Oxeye sunflower’ (Heliopsis helianthoides)
grows at Katonah; known as a “false sunflower,” it’s actually a perennial sunflower-like member of the same family, and blooms earlier in the season.

GROWING & ARRANGING

BOTH SUNFLOWERS AND RUDBECKIAS EVOKE SUNSHINE IN THE GARDEN. WHILE A WILLOWY RUDBECKIA MAY GROW TO 9 FEET, THERE’S A CERTAIN JACK-AND-THE-BEANSTALK QUALITY TO THE SUNFLOWER. YOU CAN PRACTICALLY WATCH THE STALKS PUSH UP TOWARD THE LIGHT, AS IF THEY WERE HARNESSING SOLAR ENERGY—THEY SOMETIMES GAIN 1 FOOT IN A SINGLE DAY.

In the cutting garden at Skylands we grow dozens of varieties of sunflower and rudbeckia. ‘Indian Summer’ rudbeckias, bottom left, grow well in Katonah, as do ‘Cherokee Sunset’, ‘Chim Chiminee’, ‘Goldilocks’, and R. triloba. At right, a “volunteer,” or self-seeding, sunflower turns its face to the sun on the east side of the cutting garden.

HOW TO GROW

Sunflowers and rudbeckias, in all their forms, are in the Asteraceae family, with their signature two sets of florets—the sunny ray florets (the outer petals) and the dark interior disk florets. Growing conditions for each are very similar, with one notable exception: Taller sunflower stalks require staking. Both perennial (Helianthus) and annual (Helianthus annuus) sunflowers come in hundreds of shapes and sizes, from the giant ‘Mammoth Russian’ to the dwarf ‘Music Box’. And they’re fairly easy to grow—as long as they get plenty of sun. The same goes for the approximately twenty species of Rudbeckia, whether it’s a classic black-eyed Susan (R. hirta) or the spiky-petaled R. subtomentosa. At Skylands, both grow along the border of the cutting garden; in Katonah, rudbeckias are interspersed throughout the grounds.

ZONE Planted as annuals, sunflowers are hardy in any United States zone. Perennials are hardy from Zones 4 to 10. Sunflowers love heat, and thrive in areas with long, hot summers (especially the tall, large-flowered varieties). Rudbeckias are short-lived perennials (meaning they die out after three or four years), but are sometimes treated as annuals in colder zones, such as 3 and 4.

SOIL Well-drained soil that is slightly acidic to somewhat alkaline (pH 6.0 to 7.5) and enriched with organic compost is best for sunflowers and rudbeckias. Sunflower roots need lots of space, so make sure that the soil is well dug and loose (but not so loose that the plants could blow over in the wind).

LIGHT As their name implies, sunflowers need sun—they’ll bloom best when they receive eight to even twelve hours a day. Until the flowers mature, they will track the sun as it makes its daily voyage from east to west (a process called heliotropism). Rudbeckias are also best grown in full sun, especially the larger-flowered varieties; some smaller cultivars can grow in partial shade.

CHOOSING It is easiest to grow both rudbeckias and sunflowers from seed; choose seeds over potted plants if possible. Keep their different growing habits in mind; if you’re looking to keep plants in your garden under 3 feet, you’ll want to choose shorter rudbeckias over sunflowers.

PLANTING Sunflower and the smaller rudbeckia seeds germinate very quickly. The easiest method of planting is to sow seeds (¼ to 1 inch deep) directly in the soil after the last spring frost (once the temperature of the soil has reached 55 to 60 degrees). Perennials can be started in a cold frame in spring and moved when the plants have their first two to four true leaves. In general, rudbeckias can be started inside but sunflowers grow best when they’re planted directly in the garden and not transplanted.

Plant clusters of seeds 6 inches apart. (Not all the seeds will germinate; thin the hardier seedlings when they’re about 6 inches tall.) If you’re planting larger-variety sunflowers in rows, space them 30 inches apart. Rudbeckias self-seed heavily and spread easily, so you’ll have many more plants by the second season. Space them about 18 inches or up to 2 feet apart.

WATERING Although sunflowers and rudbeckias are fairly hardy, they grow very rapidly and should be well watered about once a week, especially if you’re in a dry climate (like the Southwest) or your region is experiencing a drought. If it’s an exceptionally rainy season, you’ll only have to water if the plants are germinating. Beware of overwatering, which can cause the roots to rot.

PRUNING Rudbeckias and sunflowers will bloom even more profusely when regularly deadheaded, so use your pruners to discard only spent flower heads. (I attach some of the cut, dried sunflower heads to the garden fences for the birds to eat. Butterflies love the seeds, too, which is a bonus if you want to attract them to your garden.) To save sunflower seeds for next year, cut the blooms off early (leaving about a foot of stem) and then hang them to dry in a dark, warm place away from hungry birds. Or, in the fall, once the back of the sunflower head has changed color from green to yellow, cut it off the stem and remove the seeds with your hands.

Saving rudbeckia seeds is even easier. Wait until the petals have all fallen off the blooms and the seedpods have turned light brown. Put a seedpod in a paper bag, and leave for a few days or up to a week to fully dry. Then spread the contents on a tray and separate the seeds from other material. Store the seeds in an envelope or a glass jar. Or use my preferred method and simply let the plant spread its seeds naturally—it can do all the work on its own.

TROUBLESHOOTING Some of the very tall or heavy-headed sunflower varieties may require extra staking during stormy weather. Although sunflowers and rudbeckias are generally quite robust and low-maintenance, powdery mildew, whitefly, and fungal leaf spots can present problems, especially in more humid climates. Use an organic fungicide and ensure the plants don’t get too much water. A word of caution: Natural chemicals found in the hulls of sunflower seeds can be toxic to grasses (they’re harmless to animals and humans). It’s best to avoid growing sunflowers around grass you want to remain healthy.

In a large ceramic mixing bowl, Kevin arranged a few armfuls’ worth of rudbeckias, cut at varying heights for effect, and held in place with a cage frog. Varieties include ‘Indian Summer’, ‘Prairie Sun’, ‘Cherokee Sunset’, and ‘Chim Chiminee’, as well as Echinacea purpurea, which is another closely related member of the Asteraceae family. Some varieties of Echinacea are so similar to rudbeckia that they are both referred to by the common name of coneflower. Here, concentrating the purple coneflowers at certain focal points around the perimeter lends some order to the beautiful riot of blooms.

HOW TO ARRANGE

CUTTING Like most flowers, sunflowers and rudbeckias should be cut either in the early morning or in the evening so they won’t wilt quickly, as they would if cut at midday. It’s best to cut when the petals are just beginning to unfurl (or at the bud stage; try mixing buds and blooms in arrangements). Cut stems at a 45-degree angle. For sunflowers, leave an average of 24 inches of stem (depending on the variety) on the flower head. Place the cut flowers in a bucket of water that is lukewarm to hot to soften the stems. Kevin also likes to cut sunflowers when they’re past their prime and losing some petals. He removes the remaining petals and uses the dark flower center with its bit of green around the edges to add impact to an arrangement. Once cut, most varieties should last from a week to 10 days. Change the water daily to prolong the life of the blooms.

ARRANGING For a traditional tall sunflower, use an equally tall, bucket-shaped vase that’s fairly substantial. An opaque vessel will hide the ungainly stems. If buds are going to be the focus of the arrangement, a lower vessel works better, to allow the buds’ shape and texture to be seen and fully appreciated. To manage the branchy stems, insert them into a large flower frog or cage within a larger vessel. Sunflowers are terrific massed in a bunch or in a mixed arrangement of big-bloomed varieties such as ‘Lemon Queen’ and ‘Mammoth’, a fluffy ‘Teddy Bear’, and a dramatic red ‘Infrared’. Kevin likes to pair sunflowers and rudbeckias with grasses or with other seasonal flowers, such as snapdragons, keeping the sunflower as the dramatic centerpiece. The leaves (on small-leaf varieties) are also beautiful, so look for foliage in good condition.

Play to your surroundings when thinking about arrangements. Here, a stunning collection of mixed sunflowers from the Skylands garden complements neutral walls and faux-bois furnishings. The rustic chair and birch bark container are reflected in the choice of the vintage Albany slip-glaze pitcher, which itself resembles wood. “It’s hard to imagine this container holding anything but sunflowers,” Kevin says. A few leaves are left on the stem to provide welcome touches of bright green.

While many sunflowers have vibrant color, others, such as ‘Strawberry Blonde’, with their pale-yellow petals streaked with reddish brown, are more muted. Build upon the sturdy foundation of large flowers by adding visually lighter elements—feathery grasses, Queen Anne’s lace—and selectively keeping some of the leaves. The natural texture of a vintage Asian coiled-wicker basket (it originally served as a teapot carrier) adds to the meadow effect.

A wicker French flower basket holds a collection of classic yellow sunflowers along with a mix of ‘Indian Summer’, ‘Prairie Sun’, ‘Cherokee Sunset’, and ‘Chim Chiminee’ rudbeckias, plus ‘Oxeye sunflower’. Kevin took a multi-step approach to the unconventional vessel: first he lined the bottom of the basket with a tray, then added a wide bowl, using a tape grid (see this page) for precise placement of each flower.

Sunflowers are beautiful at all stages of their development and bloom. This arrangement will change dramatically as the large, tightly closed florets open day by day. At this stage, the accent is on the sculptural sunflower leaves and tight buds, combining the dark greens with the emerging warm yellows. You can enlist unexpected vessels, such as this antique pewter tureen, to hold arrangements. Chicken wire placed within the tureen holds the substantial flowers in place.