Salvia officinalis
Lamiaceae
Description: Culinary sage is a small, 2- to 3-foot shrub with woody stems. It has pebbly, grayish green leaves, spikes of lavender flowers, and a warm, spicy, earthy flavor that characterizes sausage and turkey stuffing. Ordinary sage is best for culinary purposes, but there are several ornamental cultivars worth the space in your herb or kitchen garden, among them ‘Berggarten’, with broad oval leaves and showy, blue-violet flowers; ‘Icterina’ (aka ‘Aurea’), with green-and-yellow variegated leaves; ‘Purpurascens’ (aka ‘Purpurea’), with purple-tinged green foliage; and ‘Tricolor’, with variegated pink, purple, white, and green leaves. Zones 3–9, although variegated cultivars may be less hardy than the species. For information on ornamental sages, see the Salvia entry.
How to grow: Culinary sage craves sun, good drainage, and average, not overly rich soil. Grow it from seed, or divide plants that are at least 2 years old. Prune in spring to keep plants shapely and strong.
Harvesting: Clip off leaves and stems throughout the growing season for culinary use. Dry individual leaves on trays in a food dehydrator or hang stems in a warm, dark, dry place like an attic to dry, then strip off leaves and store for future use. Avoid cutting back drastically in fall.
Uses: Try sage with poultry, in sausage and stuffing, with veal, fish, and liver, and in cheese and egg dishes. Perk up cooked vegetables like carrots, asparagus, tomatoes, and cabbage with a crumbling of dried leaves. If you drink tea made with dried sage leaves, according to the herbalists, you will never grow old. The dried leaves, if left on their branchlets, are wonderful in herb wreaths.
Growing salad greens other than lettuce is no harder than growing lettuce, and in many cases, a lot easier. (See the Lettuce entry for lettuce-growing tips and types.) Creating a salad that’s bursting with flavor and color is an art, but since most salad greens and enhancements go well together, it’s hard to go wrong. And fortunately, most seed companies now carry a wide range of mixes and individual species and cultivars that take the guesswork out of growing salad greens.
If you want to go beyond lettuce, try these delicious greens in your salads. You can eat some of them—spinach, arugula, and bok choy, for example—on their own, or mix them with lettuces and other greens like radicchio and mustard greens to give your salads spice and depth. Mesclun can also be the base of a salad or be mixed in with other greens. And don’t forget red, green, and savoy cabbages, which are excellent as accents in tossed salads or in starring roles in coleslaw. (See the Cabbage entry for more on growing and using cabbage.)
Arugula (Eruca vesicaria ssp. sativa): Also called rocket and roquette. Rich, peppery flavor. Sow seed in early spring or fall, thinning seedlings to space plants 4 to 6 inches apart with 10 inches between rows. Use thinnings in salads, and start harvesting mature greens in 6 to 8 weeks. Tends to bolt quickly in hot, dry weather.
Bok choy (Brassica rapa var. chinensis): Also called bok choi and pak choi. Attractive cabbage relatives with long, thick white stems and dark green leaves. Young bok choy is delicious in salads and makes a succulent coleslaw. Sow seed in early spring or fall; grow like cabbage. (See the Cabbage entry.) Plants prefer cool growing conditions. ‘Joi Choi’ is a more heat-tolerant cultivar. Space plants 8 to 12 inches apart in the row and 12 inches between rows. Harvest entire small heads or larger individual leaves.
Chicory (Cichorium intybus): A relative of endive and escarole, chicory (also called witloof chicory or Belgian endive) is delicious as a winter salad green when forced indoors. See the Endive entry for details on growing and forcing chicory.
Endive and escarole (Cichorium endivia): The lacy, cream green, frilly leaves of endive are often called frisée, while the broad-leaved forms are often sold as escarole. Start these bitter greens indoors for an early summer harvest or in the garden in summer for an autumn crop, thinning plants to stand a foot apart. (Note: That touch of bitterness is prized in Europe, adding sophistication to a potentially bland salad.) Blanch plants for a buttery color and milder flavor. For more on growing and harvesting endive and escarole, see the Endive entry.
Kale (Brassica oleracea, Acephala Group): Kale adds substance, color, and nutrition to a salad—the thick, blue-green, purple-green, green-black, or white-green leaves are packed with vitamins and minerals. Some cultivars are deeply frilled while others are deeply puckered; all add texture and variety to a mixed salad. Sow in early spring or late summer, thinning plants to 2 feet apart. Harvest the young leaves individually for salads. See the Kale entry for more on growing and harvesting kale.
Mizuna (Brassica juncea var. japonica): Attractive, compact green plant matures in 35 days, tolerates heat, and is easy to grow. Serrated leaves add a cabbagy, mustardy flavor to salads. Sow seed in early spring; grow like spinach (see the Spinach entry).
Mustard greens (Brassica juncea): Attractive red or green loose-leaf or heading mustards. Loose-leaf types mature in 45 days; heading mustards need 60 to 75 days to head up. Plants tolerate heat and light frost, and they’re easy to grow. Leaves of Oriental mustard cultivars tend not to be as hot or biting as southern mustard greens. Direct-seed in early spring or fall, barely covering with soil. Space plants 6 inches apart in the row, thinning to 10 inches; leave 10 to 12 inches between rows.
Radicchio (Cichorium intybus): This bitter Italian heading chicory has become a favorite of salad lovers everywhere. Its gorgeous deep garnet, white-based leaves add rich color and texture to salads, and the flavor adds sophistication. Start indoors as with endive and escarole for spring planting; space 6 inches apart when you transplant them outdoors. Plants form tight, 4-inch heads. See the Endive entry for more on planting and growing.
Spinach (Spinacia oleracea): This salad staple can be harvested when the leaves are small (“baby spinach”) to use whole in salads or when they’re mature. Sow seed in early spring and late summer for spring and fall crops, thinning to 4 to 6 inches apart. (Use thinnings in salads or stir-fries.) Spinach is rich in vitamins and minerals, so it’s one of the healthiest salad choices. See the Spinach entry for more on growing and harvesting spinach.
Mesclun isn’t the name of a plant—it’s a term for a mix of salad greens that are harvested and eaten together. The greens are sown close together and picked young, like spring mix. Because of mesclun’s popularity, most seed companies sell their own custom mesclun mixes. The composition of mixes varies: Some lean toward spicy, with lots of arugula and mustard greens; others are slightly bitter, going heavy on the radicchio and endive. Still other mixes focus on creating the most colorful combination.
It pays to read the packet or catalog descriptions and see what’s in a given mix before deciding which one to choose. It should also tell you the percentage of each type of seed, so you can see the actual composition of a mix before you make your selection. Here are three representative mesclun mixes to give you an idea of what’s available—or in case you want to mix up your own. There are many more!
Mesclun Salad Mix
‘Ruby’ lettuce
‘Royal Oak Leaf’ lettuce
‘Red Salad Bowl’ lettuce
Curled chervil
‘Green Ice’ lettuce
‘Paris White Cos’ lettuce
Mesclun Spicy Mix
‘Red Salad Bowl’ lettuce
‘Rossa di Treviso’ radicchio
Mizuna
‘Rocket’ arugula
‘Green Curled’ endive
European Mesclun Mix
Mix of colorful lettuce cultivars
Mizuna
Radicchio
Kale
Arugula
Mustard greens
Endive
Corn salad (mâche)
Orach
Salad greens enjoy the same growing conditions as lettuce: humus-rich, evenly moist but well-drained soil. Greens typically grow best in cool weather; hot weather makes them bolt to seed or, with plants like mustard greens, develop a more fiery flavor than plants grown in cooler spring or fall weather. Broadcast the seeds of salad greens and rake lightly to cover them, or sow seeds ¼ inch apart and as thinly as possible in rows 1½ feet apart. Sow in spring once the soil has reached at least 35°F, and again in late summer for a fall crop.
For the most beautiful salad greens you can imagine, cover seeded areas with floating row cover and leave the cover in place throughout the duration of the crop. The greens will retain their color and tenderness better under the protection of the cover. Check underneath occasionally to remove weeds (which will also enjoy the sheltered environment) and to handpick any slugs that might have found the crop.
When the seedlings have four leaves, thin plants to 6 inches apart. Make sure the crop gets at least 1 inch of water a week from rain or irrigation. To help prevent disease, try to water on sunny mornings, so the leaves can dry by evening. If you aren’t using row cover, apply a thick layer of mulch to conserve moisture, suffocate weeds around the easily damaged roots, and keep leaves free of dirt. To promote quick growth, side-dress with compost tea or fish emulsion once or twice during the growing season. See the Lettuce entry for more growing guidelines.
There’s no reason to limit your salad-growing exploits to the main crops. Add additional excitement to your salads with fresh leaves of the plants in this list. All add distinctive, delicious bites of flavor that will give your salads depth and take them from good to great. Nasturtium and chive flowers also are edible and will give your salads added beauty. See the Onion entry for tips on growing scallions; for the herbs, see the Herbs entry.
Basil
Chives
Cilantro
Garlic chives
Mint
Nasturtium
Parsley
Pepper cress
Scallions
Sorrel
Thyme
Watercress
Willow. Deciduous single- or multistemmed trees or shrubs.
Description: This genus is best known for “weeping willows,” a term applied to several species and cultivars with pendulous branches.
Salix alba, white willow, is an upright tree growing to 75 feet. Its slender, pliant branches turn an intense yellow as sap rises in spring. Leaves and catkins follow. Zones 2–8.
S. caprea, goat willow, is often confused with S. discolor, pussy willow. Both species bear the fuzzy male catkins for which pussy willow is named; both are shrubby small trees that can grow to 25 feet tall and 15 feet wide. Zones 4–8.
S. matsudana, Peking willow, grows to 40 feet. It is best known for the cultivar ‘Tortuosa’, corkscrew willow, which has contorted branches and a gnarled appearance. Zones 5–8.
How to grow: Willows grow naturally at streamside and perform best in sunny, moist locations. Willow wood is brittle, and branches often break under ice or snow. Because willows have invasive roots, plant them far away from septic systems, underground water pipes, and drains.
Landscape uses: Willows make fine accent plants and mood setters for watery or low-lying areas.
Salvia, ornamental sage. Summer- and fall-blooming annuals and perennials.
Description: Annual Salvia splendens, scarlet sage, flaunts brilliant red two-lipped blooms in spikes 8 to 30 inches over dark green leaves. Many cultivars are available in all shades of red as well as scarlet, pink, white, burgundy, salmon, and lilac.
Many other annual and tender perennial salvias are now available to add panache to the garden, including S. greggii, autumn sage (Gregg’s sage), and S. leucantha, velvet sage (Mexican bush sage). Both are shrubby plants that will survive winters in Zones 8–10; autumn sage may survive in Zone 7, though it’s often killed back to the ground in winter. And for the herb garden or a container, S. elegans, pineapple sage, is indispensable with its fruit-scented leaves and spikes of brilliant scarlet flowers. Zones 8–11.
Perennial salvias are staples of the summer flower border. S. nemorosa, woodland sage, bears numerous upright spikes of violet-blue flowers in early to midsummer over bushy plants that reach 1½ to 3 feet tall, depending on the cultivar. ‘East Friesland’ (aka ‘Ostfriesland’, deep purple) and ‘Caradonna’ (blue-violet) are two of the best cultivars of this species. Zones 4–8. The similar S. × sylvestris, wood sage, bears blue-purple flowers in plumy spikes to 2 feet above mounded leaves; some cultivars have white flowers. Purple-flowered May Night (‘Mainacht’) is a beloved cultivar. Zones 4–7.
See the Sage entry for information on the culinary species.
How to grow: Salvias grow best in full sun to very light shade and average, well-drained soil. Sow scarlet sage in early spring to plant out after the last frost, or buy bedding plants. Plant or divide perennial sage every third year in spring or fall. Deadhead for rebloom. Mulch tender perennial sage in fall to improve its chances of survival, removing mulch when growth resumes. Cut salvias back in early spring to rejuvenate them.
Landscape uses: Plant a solid bed of scarlet sage or group with other bright colors in a border. Use perennials in a border or cottage garden. All salvias are hummingbird magnets, so be sure to include some in your hummingbird garden, or grow some in containers on the deck or patio to lure hummingbirds closer to the house.
Thanks to the ingenuity of market gardeners, plant breeders, and garden product designers, any gardener can enjoy growing plants well beyond the start and end of the traditional gardening season. Season extension materials can be as simple as a modified plastic milk jug or as grand as a greenhouse, and you can extend the season by growing everything from houseplants and bulbs to herbs and vegetables.
Season extenders are materials or structures used to keep the air and soil around plants warmer. Backyard gardeners have used cold frames, cloches, and hot caps as season extenders for generations.
Organic market gardeners have raised season extension to an art form with the use of large plastic-covered structures called high tunnels, using a second layer of coverings inside the plastic tunnels to keep hardy crops such as spinach and kale producing nearly year-round in areas as chilly as Zone 5.
One simple way to extend the growing season outdoors is to start seedlings indoors ahead of the traditional schedule, and then plant the seedlings outdoors with individual cloches for protection. On a larger scale, you can use heavyweight row covers supported by wire hoops, switching to lighter-weight covers as the weather warms up. You can also reverse this process in fall, planting crops in late summer and covering them once the weather turns cool.
Keep in mind that season extenders such as cloches and row covers are most effective if you prewarm the garden soil before planting. Seeds will not germinate and transplants will suffer in cold soil, even if the air temperature is high enough. To warm the soil, put the season extender in place 1 to 2 weeks prior to planting, or cover the soil with clear or black plastic several weeks before planting.
Cloches: Cloches are small plant coverings that trap the sun’s warmth, raising the air temperature around an individual or small group of plants. Once made of glass, cloches are now made of paper or plastic, and you can easily make your own, too. Short ultraviolet rays from the sun pass through the cloche and warm the soil and air inside. The soil collects and stores the heat, then releases it slowly, creating a greenhouselike atmosphere and protecting plants from frost. The warmer conditions under a cloche also encourage growth. Commercial cloches include the popular Wall O’ Water and similar plastic tubular structures that are filled with water and set around plants. To make a simple cloche, cut off the bottom section of a gallon plastic jug and set the jug over an individual plant. Some gardeners mimic the Wall O’ Water concept by using duct tape to fashion a ring of clear plastic soda bottles to set around a tender plant (fill the bottles with water for extra heat-storage capacity). Or you can wrap clear plastic around a tomato cage to create a miniature greenhouse.
Cold frames: The best-known season extender is a cold frame. Homemade cold frames are usually made of wood with a transparent glass or plastic top; garden suppliers sell cold frames made of various types of plastic or polycarbonate with aluminum or plastic frames and bases. Use cold frames to trap the sun’s energy and keep transplants and seedlings warm at night. Hotbeds are cold frames with an auxiliary heat source. Manure, compost, a heating cable, or some other heating source maintains warm temperatures inside the frame. See the Cold Frames entry for details on using cold frames and hotbeds.
Row covers: A row cover is a versatile season extender that you can use to protect rows, small garden areas, or the whole garden from frost or cold temperatures. Row covers are sheets of transparent plastic or fabric. They’re available in different weights and sizes. By using row covers you can extend the season by a month or more. See the Row Covers entry for more details.
Doubling up: If extending your growing season captures your imagination, you may want to try building your own garden-scale plastic tunnel and raising crops inside it throughout winter. This requires covering the interior beds with cold frames or heavyweight row covers. Excellent books are available with detailed information on how to raise hardy food crops through winter with this type of system; see Recommended Reading for titles.
Growing microgreens is a fun and easy way to enjoy crispy, fresh garnishes for salads, sandwiches, and stir-fries throughout the year. Microgreens are simply vegetable and herb crops harvested very young—usually within a few weeks of germination. All you need to grow microgreens are an organic potting mix, some plastic or foam clamshell containers (take-out food containers), and seeds. In fact, growing microgreens is a great way to use up your leftover seed from the past couple of gardening seasons—seed that may no longer be germinating at its full potential but that you just hate to throw away.
To grow microgreens in a clamshell container, first cut off the lid. Use a pointed object (a shish kebab skewer works well) to poke several holes in the bottom of the container. Fill it with 1 to 1½ inches of dampened potting mix, and spread the seed thickly over the surface (about ½ inch apart). Cover the seed with about 1/4 inch of mix (less for seeds like lettuce that need light to germinate). Mist the surface thoroughly and put the container in a warm place to germinate. Check it daily; when seedlings pop through, move the container to a sunny windowsill. Use plastic flats, old trays, or aluminum pie plates as drip catchers under the containers, and bottom-water the containers as needed to keep the mix constantly moist. When your seedlings have developed one or two true leaves, use scissors to cut off the greens close to the soil surface. Or, if you’d like to try for a second cutting, cut them off about 1 inch above the soil, so the growing tip can resprout.
What crops can you use for microgreens? All traditional salad crops, plus any radishes, broccoli, and any other crop in the cabbage family (Brassicaceae). Young pea shoots are a delicious choice, as are many herbs, including dill and basil. Avoid nightshade-family crops such as tomatoes and peppers.
Indoor gardening is a great way to extend the season well into winter, especially if you’re not a person who enjoys working outdoors in cold weather or if you just want a break from outdoor gardening. Gardening indoors can be just as exciting as outdoor gardening—there’s a fabulous array of houseplants for various conditions, and a simple indoor light setup makes it possible to grow a wide variety, even if your house doesn’t have many sunny windowsills to offer; see the Houseplants entry for details. If you want to pursue gardening on a large scale in a protected environment, see the Greenhouse Gardening entry.
Another delightful indoor gardening activity is to force flowering bulbs such as narcissus and amaryllis. You can enjoy bright fresh flowers indoors beginning in late winter using this technique; see the Bulbs entry for details.
Starting seeds indoors in pots or flats is a type of season extension that any gardener with a sunny window or a simple grow-light setup can try. Whether you’re a vegetable gardener or flower enthusiast (or both), you’ll love the new world of unusual and new varieties of veggies and annuals you can grow when you start your own plants from seed beginning in late winter. And at any time of year, you can start seeds for a nutritious and tasty crop of microgreens, as described at left. For full information on indoor seed starting, see the Seed Starting and Seed Saving entry.
Sedum, stonecrop. Perennial flowers or groundcovers.
Description: Sedums have succulent green leaves on fleshy stems that form somewhat sprawling, trailing rosettes. Leaves of many species turn red in late fall; some cultivars have brilliantly colored or variegated foliage. Most sedums bloom from May through August with white or yellow flowers.
Several upright perennials, including the popular hybrid ‘Autumn Joy’/’Herbstfreude’, formerly included in the genus Sedum have been reclassified as Hylotelephium. See that entry for information about the upright stonecrop species. Other species formerly included in Sedum are reclassified as Phedimus or Rhodiola. If you are seeking these versatile plants for a rock garden or dry, sunny site, bear in mind that they may appear under new names.
Creeping or low-growing species sedums make good groundcovers for dry, sunny or lightly shaded sites. S. kamtschaticum (also called Phedimus kamtschaticus), orange or Kamschatka stonecrop, is a 2- to 4-inch trailer with yellow starlike flowers that appear in May, complementing its light green leaves. Sedum album, white stonecrop, is trailing, with short leaves that turn a reddish color in winter. The flowers open white to pink in late summer.
S. spurium (Phedimus spurius), two-row stone-crop, grows 2 to 6 inches tall and forms mats of foliage that turns bronze in fall; it produces open clusters of pink flowers in summer. Zones 3–8.
S. ternatum, woodland stonecrop, tolerates partial shade and moist soil better than many sedums and grows to 3 to 6 inches tall. Creeping stems root at the nodes; clusters of small, starry, white flowers bloom in spring. Zones 4–8.
How to grow: Sedums are easy to grow in any well-drained, average soil in sun or light shade. They are tolerant of poor soil and hot, dry weather. Propagate them in spring or summer by division or cuttings.
Landscape uses: Use the smaller species as groundcovers for banks, or plant in pots, rock gardens, and the front of borders. They also look wonderful trailing over a stone wall.
Seeds come in an amazing variety of forms and sizes, from the dustlike seeds of begonias to the hefty coconut. But all seeds have one quality in common: They are living links between generations of plants, carrying the vital genetic information that directs the growth and development of the next plant generation. Seeds are alive. They even carry on respiration—absorbing oxygen and giving off carbon dioxide.
As long as a seed is kept cool and dry, its life processes hum along on low. Most seeds remain viable for 1 to 3 years after they ripen on a plant. Some, such as parsnip seed, can’t be counted on to sprout after more than 1 year, but others, like muskmelon seeds, can germinate after 5 years or more if storage conditions are favorable. In fact, certain seeds recovered from archaeological digs have proven viable even though they are hundreds of years old.
Growing your own plants from seed can be one of the most satisfying and intriguing aspects of gardening. Almost all gardeners have grown vegetables from seed. But if you’re interested in a challenge, you can start your own annuals, perennials, herbs, and even trees from seed. For tips on buying seeds, see Smart Shopping: Buying the Best Seeds.
Moisture and warmth encourage seeds to germinate. When a seed absorbs water, its internal pressure rises, rupturing the seed coat. Growth hormones within the seed go into action, directing vital compounds to where they are needed and encouraging the growth of new tissue.
All of these changes depend on temperature as well. Most garden seeds started indoors germinate best at a soil temperature of 75° to 90°F. Sprouting seeds also need air. A porous soil kept evenly moist (but not swampy) will provide enough air to support the germination process. Seeds often rot if they are submerged in water for days or if they are planted in completely waterlogged soil.
After the germination process has been in action for several days (or, in some cases, for a week or more), a seed will change in visible ways. The root emerges and starts to grow, the stem grows longer, and then the cotyledons unfold. Once germination has begun, you can’t reverse the process. If the sprouted seed continues to receive moisture, warmth, air, and light, it keeps growing. If not, it dies.
Most seeds have no specific light requirement for germination. However, some kinds of seeds need light to break dormancy and germinate, including many tiny seeds, such as begonia, columbines (Aquilegia spp.), snapdragon (Antirrhinum), and petunia seeds. Some larger seeds such as impatiens, dill, spider flower (Cleome hassleriana), and sweet alyssum (Lobularia maritima) are also best left uncovered. Sow light-sensitive seeds on the surface of fine, moist soil or seed-starting mix. Just press them onto the surface of the medium. Then cover them loosely with clear plastic to retain moisture, or mist them frequently.
A few seeds require darkness to germinate. For example, Madagascar periwinkle (Catharanthus roseus) seed germinates far better if the flat is covered with black plastic or kept in a dark closet until seeds sprout.
Other seeds will germinate readily only if planted soon after they ripen. Angelica, hawthorns (Crataegus spp,) and Solomon’s seals (Polygonatum spp.) are three types of seed best sown soon after they are collected.
Check seed packet information to find out whether the seeds you want to raise have special germination requirements.
Seed. A plant embryo and its supply of nutrients, often surrounded by a protective seed coat.
Germination. The beginning of the growth of a seed.
Viable. Capable of germinating; alive.
Seed dormancy. A state of reduced biochemical activity that persists until certain conditions occur that trigger germination.
Seedling. A young plant grown from seed. Commonly, plants grown from seed are termed seedlings until they are first transplanted.
Cotyledon. The leaf (or leaves), present in the dormant seed, that is the first to unfold as a seed germinates. Cotyledons often look different from the leaves that follow them. In seeds such as beans, they contain stored nutrients. Also called seed leaves.
Endosperm. Specialized layer of tissue that surrounds the embryo.
Scarification. Nicking or wearing down hard seed coats to encourage germination.
Stratification. Exposing seeds to a period of cool/moist (35° to 40°F) or warm/moist (68° to 86°F) conditions that break dormancy.
Damping-off. A disease caused by various fungi that results in seedling stems that shrivel and collapse at soil level.
Some kinds of seeds require certain treatments before they’ll start to germinate. No matter how ideal conditions are for germination, the seeds will remain dormant if the pregermination requirements have not been met. This characteristic, called innate dormancy, helps ensure survival in nature, because the seeds wait out winter or the dry season before sprouting.
Certain seeds require a period of moist cold. This mechanism is common in plants native to climates with cold winters, especially perennials, trees, and shrubs. Other seeds have chemicals in their seed coats that must be soaked away before the seeds will germinate. Some seeds are slow to absorb enough water to start germination because of thick or impermeable seed coats. Plants native to areas with seasonal dry spells often have this type of dormancy. If you understand these dormancy mechanisms, you can work around them and coax the seeds to germinate.
Even seeds that don’t have dormancy requirements may be slow to germinate. Appropriate pretreatment can significantly increase germination rate and reduce germination time.
Stratification: Some seeds must be exposed to cold, moist conditions for a certain period before they will break dormancy and germinate. Stratification simulates natural conditions when a seed overwinters in cold, moist ground. To stratify seeds, layer them in pots or plastic bags filled with damp sphagnum moss, peat moss, or vermiculite and keep them in a cold place (34° to 40°F) for 1 to 4 months. Or plant seeds in fall or late winter, mulch the tops of the pots with tiny gravel, and set them outside in a cold, protected spot where they will germinate in spring.
Seeds of various perennials, including wild bleeding heart (Dicentra eximia), gas plant (Dictamnus albus), and cardinal flower (Lobelia cardinalis), need a cold period. You can plant them outdoors in fall, or spring plant after giving them a cold treatment. The following illustration shows how to prepare seeds for cold treatment. Many woody plant seeds also require stratification, including birches (Betula spp.), dogwoods (Cornus spp.), false cypresses (Chamaecyparis spp.), and spruces (Picea spp.). Some tree and shrub seeds, including arborvitaes (Thuja spp.), cotoneasters, and lilacs (Syringa spp.), are double dormant, which means they require a warm, moist stratification period followed by a cold period to germinate. If planted outdoors in fall, these seeds may not germinate for 2 years.
Scarification: Some seeds, such as morning glory, sweet pea, okra, and others, have hard seed coats that inhibit water absorption. To make a hard-coated seed absorb water more readily, nick the seed coat. Be careful not to damage the embryo inside the seed. On large seeds, use a knife to cut a notch in the seed coat, or make several strokes with a sharp-edged file. Scarify medium-size or small seeds by rubbing them between two sheets of sandpaper. After scarifying, soak seeds in lukewarm water for several hours before planting.
Presoaking: Even seeds that have thin seed coats can benefit from a soak in lukewarm water for several hours before planting. Large seeds such as peas and okra will germinate faster if soaked overnight first. Before planting, drain the seeds and dry them briefly on paper towels to make them easier to handle.
Presprouting: Presprouting takes seeds one step further than presoaking. It’s a good way to handle such seeds as melons, squash, and their relatives, which need plenty of warmth for germination. Because sprouted seeds can tolerate cooler temperatures, you can concentrate your population of germinating seeds in one warm place and farm out the sprouted seedlings to cooler spots, where they will receive plenty of light. See Presprouting Seeds sidebar for step-by-step instructions for this technique.
Sprouted seeds are fragile; handle them with great care. Be sure to plant them before their roots grow together and tangle. Plant sprouted seeds in individual containers of premoistened potting mix. Cover them gently but firmly with potting mix and treat them as you would any container-raised seedling. Sprouted seeds may be planted directly in the garden, but it is better to keep them in containers until the roots become established.
Preparing seeds for stratification. Layer large seeds with damp sphagnum moss in a labeled plastic container with a tight-fitting lid for cold storage. Mix small seeds into a seed-starting medium in a plastic bag. Close with a twist tie and label.
Here are some tips to help you to get the most from your seed order.
•Send for several seed catalogs or visit several Web sites so you can compare offerings and prices.
•Seed catalogs can be handy for reference; keep them on a shelf in your seed-starting area.
•Some companies offer small seed packets at reasonable prices. Seed mixtures give you a wide variety of plants from a single packet.
•Days to maturity (the number of days from seed sowing or transplanting to harvest) is an average—the actual days in your area may be different.
•Hybrids may offer advantages such as early harvest or high yields but hybrid seed is usually more expensive. Open-pollinated cultivars may taste better and produce over a longer season, and they tend to be cheaper.
•Some seed is routinely treated with synthetic chemical fungicide. Specify untreated seed if you prefer it, or buy from companies that sell only untreated seed.
•Read descriptions and choose cultivars with qualities that are important to you.
•Certain suppliers specialize in plants suited to specific regions of the country.
•All-America Selections seeds grow and produce well over a wide range of conditions.
Starting seeds indoors will give you earlier vegetables and flowers, and your cultivar choices will be endless. The process of germination may seem complex, but the act of seed planting is reassuringly simple. Just take it step-by-step, and you’ll soon be presiding over a healthy crop of seedlings.
Select your work area—a surface at a comfortable height and close to a water supply where you’ll have room to spread things out. Assemble your equipment: seed-starting containers, starting medium or soil mix, watering can, labels, marking pen, and seed packets.
You can start seeds in almost any kind of container that will hold 1 to 2 inches of starting medium and won’t become easily waterlogged. Once seedlings form more roots and develop their true leaves, though, they grow best in containers that provide more space for root growth and have holes for drainage.
You can start seedlings in open flats, in individual sections of a market pack, or in pots. Individual containers are preferable, because the less you disturb tender roots, the better. Some containers, such as peat pots, paper pots, and soil blocks, go right into the garden with the plant during transplanting. Other pots must be slipped off the root-ball before planting.
Square or rectangular containers make better use of space and provide more root area than round ones do. However, individual containers dry out faster than open flats. Many gardeners start seeds in open flats and transplant seedlings to individual containers after the first true leaves unfold. Choose flats and containers to match the number and types of plants you wish to grow and the space you have available.
Excellent seed-starting systems are available from garden centers and mail-order suppliers. You can also build your own wooden flats. If you raise large numbers of seedlings, it’s useful to have interchangeable, standard-size flats and inserts.
You can reuse your seedling containers for many years. To prevent problems with damping-off disease, you may want to sanitize flats at the end of the season by dipping them in a 10 percent solution of household bleach (1 cup of bleach plus 9 cups of water).
Homemade containers: You can recycle milk cartons and many types of plastic containers as seed-starting pots. Just be sure to poke a drainage hole in the bottom of each. Cut lengths of clothes hanger as a frame for your flats so you can wrap them in plastic to encourage germination. You can bend the wire to fit into a plastic flat filled with pots or six-packs, or staple the wire to the sides of a wooden flat as shown at right. Use clear plastic wrap or plastic bags (like the ones from the dry cleaner) to enclose the flat.
Two make-at-home seed-starting containers are newspaper pots and soil blocks. To make pots from newspaper, begin by cutting bands of newspaper about twice as wide as the desired height of a pot (about 4 inches wide for a 2-inch-high pot). Wrap a band around the lower half of a jar a few times, and secure it with masking tape. Then form the bottom of the pot by creasing and folding the paper in around the bottom of the jar. You can also put a piece of tape across the pot bottom to hold it more securely in place. Slip the newspaper pot off the jar. Set your pots in high-sided trays with their sides touching. When you fill them with potting mix, they will support one another. There are also commercial molds for making newspaper pots.
Soil blocks encourage well-branched roots and produce good seedlings. You can buy molds to make soil blocks, but making them is a messy, labor-intensive process.
Begin by mixing a wheelbarrow-load of potting soil. Use plenty of peat moss or coir and lots of water to make a thick, wet, gummy mass with the texture of peanut butter. Jam the soil-block mold into the block mix. Press the mold hard against the bottom of the wheelbarrow, and then lift and eject the blocks from the mold onto a tray. Then arrange the blocks in flats and plant directly into them. Don’t let soil blocks dry out: Because of their high peat content, they don’t absorb moisture well once they have become dry. Water from the bottom or mist gently until roots grow. Once roots fill the blocks, they become solid and easy to handle.
Homemade greenhouses. A homemade greenhouse fashioned from a flat, some clothes-hanger wire, and a large plastic bag is a simple, inexpensive setup that provides the high-humidity environment germinating seeds require.
Sprouting seeds before you plant them can boost germination rates and give you more control when working with expensive or scarce seeds. Here’s how to presprout seeds.
1.Spread a double layer of damp paper towels on a flat surface.
2.Evenly space seeds 1 inch or so apart on the moist towels.
3.Roll up the towels, being careful to keep the seeds from bunching up.
4.Label the seed roll and enclose it in a plastic bag. Close the bag loosely—germinating seeds need some air. You can put several rolls in one plastic bag.
5.Put the seeds in a warm place—near a water heater or on top of a refrigerator. Make a note on your calendar to check them in 2 or 3 days.
6.After the first inspection, check the seeds daily for signs of sprouting.
Plant the sprouted seeds in individual containers using a fine, loose potting soil mix, or plant them directly in the garden. Handle them gently. The fleshy roots and stems are easily broken. Then treat as you would other newly germinated seedlings.
Seeds contain enough nutrients to nourish themselves through sprouting, so a seed-starting mix does not have to contain nutrients. It should be free of weed seeds and toxic substances, hold moisture well, and provide plenty of air spaces. Don’t use plain garden soil to start seedlings; it hardens into a dense mass that delicate young roots can’t penetrate.
Make your own seed-starting mix by combining one part vermiculite or perlite with one part peat moss, milled sphagnum moss, coir, or well-screened compost. Or buy bagged seed-starting mix. Let your seedlings grow in such a mixture until they develop their first true leaves, and then transplant into a nutrient-rich potting mix (be sure the mix you choose is labeled organic, or check the list of ingredients, and avoid mixes that contain added synthetic fertilizer). To make your own potting mix, combine equal parts compost and vermiculite. For more recipes for mixes, see the Houseplants entry. For safe handling instructions for seed-starting and potting mixes, see the Container Gardening entry.
Some gardeners prefer to plant seeds directly in potting mix and eliminate transplanting. Planting in large individual pots is ideal for plants such as squash and melons that won’t grow well if their roots are disturbed.
Moisten the planting mix before you fill your containers, especially if it contains peat moss or milled sphagnum moss. Use warm water, and allow the mix time to absorb it. When you squeeze a handful of mix it should hold together and feel moist, but it shouldn’t drip.
If you’re sowing directly in flats, first line the bottom with a sheet of newspaper to keep soil from washing out. Scoop premoistened planting medium into the containers or flats, and spread it out. Tap the filled container on your work surface to settle the medium, and smooth the surface with your hand. Don’t pack it down tightly.
Space large seeds at least 1 inch apart, planting two or three seeds in each pot (snip off the weaker seedlings later). Plant medium-size seeds ½ to 1 inch apart, and tiny ones about ½ inch apart. If you’re sowing only a few seeds, use your fingertips or tweezers to place them precisely. To sprinkle seeds evenly, try one of these methods.
Take a pinch of seeds between your thumb and forefinger and slowly rotate thumb against finger—try to release the seeds gradually while moving your hand over the container.
Scatter seeds from a spoon.
Sow seeds directly from the corner of the packet by tapping the packet gently to make the seeds drop out one by one.
Mix fine seeds with dry sand, and scatter the mixture from a saltshaker.
To sow seeds in tiny furrows or rows, just make shallow ¼- to ½-inch-deep depressions in the soil with a plant label or an old pencil. Space the seeds along the bottom of the furrow.
Cover the seeds to a depth of three times their thickness by carefully sprinkling them with light, dry potting soil or seed-starting medium. Don’t cover seeds that need light to germinate (check the seed packet for special germination requirements). Instead, gently pat the surface of the mix so the seeds and mix have good contact.
Write a label for each kind of seed you plant and put it in the flat or pot as soon as the seeds are planted, before any mix-ups occur.
Set the flats or pots in shallow containers of water and let them soak until the surface of the planting medium looks moist. Or you can gently mist the mix. If you water from the top, use a watering can with a rose nozzle to get a gentle stream that won’t wash the seeds out of place.
Cover the container, using clear plastic or a floating row cover for seeds that need light, or black plastic, damp newspaper, or burlap for those that prefer the dark.
Finally, put the containers of planted seeds in a warm place where you can check them daily. Unless the seeds need light to germinate, you can save space the first few days by stacking flats. Just be sure the bottom of a flat doesn’t actually rest on the planting mix of the flat below. Check the flats daily; unstack as soon as the seeds start to sprout. Keep the soil moist but not waterlogged. As soon as you notice sprouts nudging above the soil surface, expose the flat to light.
To plan the best time to start seedlings indoors in spring, you need to know the approximate date of the average last spring frost in your area. Count back from that date the number of weeks indicated below to determine the appropriate starting date for various crops. An asterisk (*) indicates a cold-hardy plant that can be set out 4 to 6 weeks before the last frost.
•12 to 14 weeks: Onions,* leeks,* chives,* pansies,* impatiens, and coleus
•8 to 12 weeks: Peppers, lettuce,* cabbage-family crops,* petunias, snapdragons,* alyssum,* and other hardy annual flowers
•6 to 8 weeks: Eggplants, tomatoes
•5 to 6 weeks: Zinnias, cockscombs (Celosia spp.), marigolds, other tender annuals
•2 to 4 weeks: Cucumbers, melons, okra, pumpkins, squash
Seedlings need regular attention. Provide the right amount of light, heat, and humidity to grow robust, healthy seedlings.
Light: Seedlings need more intense light than full-grown plants. If they don’t get enough light, or if the light isn’t strong enough, they will become spindly and leggy. Sixteen hours of light a day is ideal, 14 hours is acceptable, and plants can get along with 12 hours in a cool location. Up to 18 hours will do no harm, but most plants won’t thrive in continuous light.
Windowsills are a popular spot for starting seedlings. Wide windowsills are suitable as is, but you can also widen narrow windowsills by installing shelf brackets and boards. Keep in mind that the air close to the window glass can be too cold for some tender seedlings, especially at night. Pull curtains or prop up cardboard next to the glass at night for protection. Short winter days provide inadequate light for many plants. Turn plants regularly to prevent them from developing a one-sided leaning, or rig up a mirror or a reflector made of aluminum foil and cardboard. A sunporch offers more room and often longer exposure to the sun than do windowsills, and the cooler temperatures in a sunporch can be great for cold-loving plants.
If you have a greenhouse, you can easily raise high-quality seedlings in quantity. Cold frames can shelter small batches of cold-hardy seedlings like pansies and broccoli early in the season, followed by tomatoes and annual flowers as the season progresses. The addition of heating can transform a cold frame into a hotbed. For more information on greenhouses, cold frames, and hotbeds, see the Greenhouse Gardening and Cold Frames entries.
Fluorescent lights use energy and will raise your electric bill, but they do help in raising good seedlings. Special plant-growth lights, often called grow lights, are expensive. The light from less-expensive cool-white tubes produces comparable plants. For best results, mount your lights using chains and “S” hooks, so you can easily raise the height of the lights as the seedlings grow. Keep tubes close to the seedlings; no more than 3 inches away for the first few weeks. Then raise the lights to 4 or 6 inches above the top of the seedlings.
Water: Seedlings need a steady supply of moisture. Dry air in a heated house can suck moisture rapidly from the shallow soil in seedling flats. Check for dryness by poking your finger into the soil and by lifting the flats. A flat with dry soil weighs less than one that’s well watered. For delicate seedlings, bottom watering is best, since it does not disturb roots and helps prevent disease problems such as damping-off. Use tepid water rather than cold water to water seedlings, especially warmth-loving plants like okra, eggplant, and melons. In a warm, dry, house, seedlings may need to be watered every 2 to 3 days or even more frequently.
Temperature: Young plants require less warmth than germinating seedlings. Average room temperatures of about 60° to 70°F, dropping by about 10°F at night, will keep most seedlings growing steadily. Slightly lower temperatures will make seedlings stocky but slower growing. Cool-weather plants such as cabbage and lettuce prefer cooler temperatures.
Temperatures of 30° to 45°F can cause chilling injury in some warmth-loving flowers and vegetables. Temperatures higher than about 75°F tend to produce weak, spindly plants that are vulnerable to harsh outdoor conditions.
Ventilation: Remove any plastic or other coverings as soon as seeds sprout. Lack of air circulation can lead to the development of damping-off.
Fertilizer: Seedlings growing in a soilless or lean mix will need small doses of plant food, starting at the time the first true leaves develop. Use a half-strength fertilizer solution once a week for the first 3 weeks. Fish emulsion and compost teas are good choices. After that, use a full-strength solution every 10 to 14 days. Seedlings grown in a potting mix that contains compost or other nutrients may not need supplementary feeding for several weeks. If the seedlings start looking pale, feed as above. See the Compost entry for instructions for making compost tea.
Transplanting: Most gardeners tend to sow seeds thickly, but seedlings grow faster, develop better, and are less prone to disease if they have plenty of space and good soil. Transplanting gives you a chance to select the best seedlings and to move them into a larger container of richer soil. You can transplant seedlings from their nursery flat to another flat with wider spacing, or you can move them to individual pots. Seedlings are ready for transplanting when they have developed their first set of true leaves. For details on how to handle seedlings see the Transplanting entry.
Before you can plant your seedlings in the garden, you must prepare them for life outdoors. Sheltered plants are unaccustomed to wind, strong sun, cold air, and varying temperatures. They will do better if you help them develop tougher tissues gradually, before you plant them outside.
When it’s time to plant the hardened-off seedlings in the outdoor garden, wait for an overcast or drizzly day, or plant them in the late afternoon. Seedlings will suffer less stress if they are not set out during a hot, sunny day. If you plant transplants out just before a rain, they’ll get off to a good start, and you’ll have less watering to do.
After planting out, you may want to put wooden bushel baskets or cut-open plastic jugs over seedlings or drape the row with a floating row cover to protect them from sun, wind, or frost. If the sun is strong or the plants are in an exposed location, water the soil around them several times during their first week in the ground, until their roots take hold. If plants wilt, water the soil promptly and shade the plants from the sun for a day or two.
For more information on hardening off and planting out seedlings, see the Transplanting entry.
You can plant seeds of many flowers, herbs, and vegetables directly in the garden. If you live where winters are mild, you can sow seeds outside pretty much year-round. In cold-winter areas, the outdoor seed-sowing season begins in spring when the ground thaws and continues until early autumn.
When the soil is soft enough to dig and dry enough to crumble readily in your hand, you can make your first outdoor plantings. Don’t try to work the soil while it is wet (see the Soil entry for information on determining when the soil is ready to dig and suitable preparation techniques.) Start with the hardiest seeds, such as peas and radishes, and gradually work up to more tender crops as the season progresses and frost danger diminishes and finally disappears.
Avoid stepping on the seedbed; compacted soil lacks the air spaces so necessary for good root growth. Sprinkle seed thinly over the entire bed, or plant in straight rows, using a string stretched between two sticks to help you mark out the rows. Follow seed packet directions for seed spacing: Thick stands of seedlings compete with each other just like weeds and are more prone to disease problems such as damping-off. After you have sown the seeds, mark the spot with a label, and record the planting on your garden calendar or plan. For more detailed instructions on outdoor seed sowing, see the Planting entry.
To figure the latest possible planting date for late-summer seed sowing, subtract the average days to maturity for the crop from the average date of your first hard frost. Subtract 5 to 10 extra days to compensate for cooler fall nights and slower growth. If frost comes in mid-October, for instance, make a final planting of 50-day lettuce in early to mid-August. If you use season extenders like floating row covers, delay the final planting date a few weeks.
Saving seeds is fun, and you can save a bit of money by doing it. You can save seeds from individual plants with traits you desire, such as earliness, disease resistance, high yield, or flower color. By carefully selecting individual plants each year and saving their seed, you can develop strains that are uniquely suited to your growing conditions.
Seed saving is also an important way to perpetuate heirloom varieties that are in danger of becoming extinct. For further information, see the Heirloom Plants entry.
Selecting seed to save: Only save seed from plants grown from open-pollinated seed. Open-pollinated cultivars produce seed that comes true—the seedlings are very like the parents. They also are somewhat variable by nature, and repeated selection for a particular character will yield a strain that is slightly different from the original one. Seed harvested from hybrid plants produces seedlings unlike the parents and in most cases inferior to them.
When selecting plants to save seed from, choose those that are vigorous, disease-free, and outstanding in whatever qualities you wish to encourage. Mark chosen plants with a stake or colored string so you won’t forget and harvest them for other purposes by mistake.
Some garden plants, such as tomatoes, peas, and lettuce, are self-pollinated. Each flower pollinates itself. You don’t have to take any precautions to prevent one cultivar from crossing with another—just let the seed mature, and harvest it.
Others, such as corn and plants of the pumpkin, squash, and cabbage families, are cross-pollinated and can cross with other cultivars of the same plant. To keep a strain pure, keep plants from which you want to save seed separate from other blooming cultivars of the same species by at least 200 feet. Or use bags to cover the blooms you plan to harvest seed from before they open, and pollinate them by hand with flowers of the same cultivar.
Certain garden plants normally grown as annuals, such as carrots and cabbage, are biennials—these crops will not produce seed the first year. Select superior plants and allow them to overwinter in place if possible. If you can’t work around them, transplant them carefully to a new location.
Harvesting: Pick seedpods when they have turned dry and brittle but before they break open and scatter the seed. Some plants have very fragile seedpods or ripen unevenly. Cover the pods of these plants with a bag before the seeds ripen completely, and tie it snugly to the stem so seeds can’t escape. Remove the seeds from the pods after harvesting. You can split the pods by hand or thresh the seeds out by beating them with a stick on a large piece of plastic.
Allow fleshy fruits like tomatoes, squash, and cucumbers to get a little overripe on the plant before harvesting them, but don’t allow them to start to rot. Separate the seeds from the flesh and wash them clean in water. Some seeds are covered with a thick, jellylike coating. Clean the seeds by removing as much flesh as possible by letting them sit in water in a jar for a few days. The seeds will sink to the bottom of the jar and the pulp will float. Pour off the pulp and dry the seeds.
Drying and storing: After gathering seeds, spread them on newspaper and let them air-dry for about a week. Write seed names on the newspaper so you don’t get them confused. Then pack them away in airtight jars and keep them in a cool, dry place. Label packaged seeds with cultivar, date, and any other pertinent information. Remember that heat and dampness will shorten the seed’s period of viability.
If your seeds fail to germinate or if only a few sprout, it is probably due to one or more of these factors.
•Old seed that is no longer viable
•Seed produced under poor growing conditions that is not viable
•Seed that is damaged
•Too much or not enough moisture
•Temperature too high or too low
•Germination-inhibiting substances in the soil (herbicide residues, for example) or high salt content in soil
•Top watering or heavy rain washed seeds out of soil mix or covered them too deeply, or seed was planted too deeply to start with
•Damping-off disease
•Seeds not in good contact with soil
•Lack of light or lack of darkness for seeds that need these for germination
•Dormancy requirement not met
Gardening in the shade challenges the talents of many gardeners because they fight the shady conditions rather than adapting to them. You can’t grow a lovely lawn or prairie-style wildflower meadow under trees. But you can grow a diverse, beautiful garden. Instead of struggling to grow sun-loving flowers and lawn grass on a shady site, why not design a garden that will actually thrive in shade? By carefully choosing flowering shrubs, perennials, annuals, groundcovers, and ferns adapted to shady conditions, your garden will be not only colorful and interesting but also easy to care for!
Study your shady site to decide if you have dense, light, or partial shade. In partial shade, where some direct sun shines for a few hours a day, you’ll be able to grow a wider selection of plants. Light or dappled shade also allows a wider selection than dense all-day shade cast from a thick-foliaged tree. If tree shade is very dense, you might want to thin out a few tree branches (cutting them off at the trunk) so that more light reaches the ground, creating a light or filtered shade. You may have to thin out branches every few years to maintain the effect.
In a shady area, it’s often the case that poor, dry soil limits plant growth more than lack of light. Shade spots under trees can often be remarkably dry, because the trees’ surface roots suck up all the available moisture and nutrients. The lack of moisture often limits your endeavors more than the shade. You’ll know if dry, root-clogged soil poses a problem because the ground will feel hard and compacted, and you’ll have trouble digging a hole with a trowel.
If the soil in your shady spot is compacted, you can layer chopped-up leaves and twigs over the area. In a year or so, they will decompose into a rich humus. Chop the dry leaves to the size of 50-cent pieces with a bagging lawn mower, and spread them several inches deep beneath the tree boughs. Sprinkle the leaves with a compost activator and keep them moist. Repeat this procedure annually until the leaves have rotted into a deep humus. By then, earthworms will have moved in and begun to loosen up the subsoil. Only when you have a loose, friable soil can you begin installing a diverse shade garden, though tough ground-covers such as epimediums (Epimedium spp.) will grow in dense tree shade and poor soil.
Sometimes tree roots interfere with digging a planting hole for a shade-loving shrub. When this happens, dig an extra-large planting hole and sever all interfering tree roots smaller than 1 inch in diameter. Mulch the soil with compost to nourish the young shrub. The large planting hole should give the shrub enough growing room to get established before tree roots return.
For the most pleasing effect, arrange plants beginning with the tallest at the back of the garden, or in the center if it is to be viewed from all sides, and filling in with the shortest. You might start by planting a shade-loving understory tree, then arranging groups of broad-leaved evergreen shrubs. After these woody plants are in place, add large groups of flowering perennials and underplant them with groundcovers to keep the soil cool and moist. Spring-flowering bulbs often flourish beneath deciduous trees, soaking up all the sun they need in spring before the tree leaves emerge. Plant them in large drifts together with the perennials.
Choose white and pastel-colored flowers as well as white-, cream-, or yellow-variegated and gold-and chartreuse-leaved foliage plants, such as hostas and golden hakone grass, for your shady site. These light colors pop out of the shadows rather than receding into the gloom like red or purple flowers tend to do. For more on designing a garden, see the Garden Design entry; for more on landscaping your shady areas, see the Landscaping entry.
With a careful selection and placement of plants, you can transform your dim spot into a cool, flowery retreat. It just might become the best-looking part of your yard.
The wide selection of plants listed here will brighten up any shady corner. Most prefer partial or filtered shade, but some can do well even in full shade. Check plant hardiness of perennials, groundcovers, and shrubs and choose plants that are hardy in your area. If you have room, consider flowering understory trees like dogwoods and redbuds that do well in woodland conditions. For more plants that tolerate shady conditions, see the Ferns entry, and the plant lists in Annuals for Shade, Biennials for Sun and Shade, Groundcovers for Dry Shade, and Best Perennials for Shade.
Annuals
Begonia × semperflorens-cultorum hybrids (wax begonias)
Browallia speciosa (browallia)
Plectranthus scutellarioides (coleus)
Impatiens walleriana (impatiens)
Myosotis sylvatica (woodland forget-me-not)
Torenia fournieri (wishbone flower)
Viola × wittrockiana (pansy)
Perennials
Astilbe spp. and cultivars (astilbes)
Dicentra eximia (fringed bleeding heart)
Dicentra spectabilis (common bleeding heart)
Digitalis grandiflora (yellow foxglove)
Digitalis purpurea (common foxglove; reseeding biennial)
Filipendula ulmaria (queen-of-the-meadow)
Helleborus spp. (hellebores)
Hemerocallis spp. and cultivars (daylilies)
Heuchera spp. and cultivars (heucheras, alumroots)
Hosta spp. and cultivars (hostas)
Mertensia virginica (Virginia bluebells)
Osmunda cinnamomea (cinnamon fern)
Phlox divaricata (wild blue phlox)
Phlox stolonifera (creeping phlox)
Polygonatum spp. (Solomon’s seals)
Primula spp. (primroses)
Tiarella cordifolia (Allegheny foamflower)
Groundcovers
Ajuga reptans (ajuga)
Asarum spp. (wild gingers)
Bergenia crassifolia (heartleaf bergenia)
Carex spp. (sedges)
Convallaria majalis (lily of the valley)
Fragaria vesca (alpine strawberry)
Galium odoratum (sweet woodruff)
Epimedium spp. (epimediums)
Hakonechloa macra (hakone grass)
Lamium maculatum (spotted dead nettle)
Liriope spp. (lilyturfs)
Mitchella repens (partridgeberry)
Pachysandra procumbens (Allegheny spurge)
Pachysandra terminalis (Japanese pachysandra)
Shrubs
Calycanthus floridus (Carolina allspice)
Daphne cneorum (rose daphne)
Ilex crenata (Japanese holly)
Kalmia latifolia (mountain laurel)
Kerria japonica ‘Variegata’ (variegated Japanese kerria)
Leucothoe spp. (leucothoes)
Mahonia spp. (mahonias and Oregon grapes)
Nandina domestica (heavenly bamboo)
Prunus laurocerasus (cherry laurel)
Rhododendron spp. and cultivars (rhododendrons and azaleas)
Ribes alpinum (alpine currant)
Sarcococca hookeriana (sweet box)
Skimmia japonica (Japanese skimmia)
Some of the most familiar and beautiful plants around our homes are shrubs. Arching mounds of forsythia, the formal evergreen shape of a false cypress (Chamaecyparis spp.), and the layered, flower-laden branches of a viburnum (Viburnum spp.) show the diversity of these woody perennials. Shrubs have multiple stems and range in height from a few inches to approximately 15 feet at maturity, although individual shrubs may grow as high as 30 feet. A shrub trained to a single stem, called a standard, resembles a miniature tree.
It’s hard to imagine a home landscape without shrubs. Their combined features of easy care, interesting forms, and attractive flowers, foliage, and fruit make them a great asset to all gardens.
Deciduous shrubs drop their leaves at the end of each growing season and grow new leaves the following spring. Leaves may first change color—redvein enkianthus (Enkianthus campanulatus) and fothergillas (Fothergilla spp.) feature leaves with spectacular autumn color—but after leaf fall, the shrub enters winter dormancy.
Evergreen shrubs have leaves year-round. They do drop some or all of their old leaves each year, but they always have new leaves to keep them looking green. Narrow-leaved or needle evergreens, such as junipers (Juniperus spp.) and bird’snest spruce (Picea abies ‘Nidiformis’) have needles or scalelike leaves. Broad-leaved evergreens such as boxwoods (Buxus spp.) and mountain laurels (Kalmia latifolia) have wide, generally thick leaves.
Semievergreen shrubs such as glossy abelia (Abelia × grandiflora) keep at least part of their leaves well into winter. These are often evergreen in the South and semievergreen farther north.
A few genera of shrubs contain both deciduous and evergreen species. For example, the handsome evergreen leaves of American holly (Ilex opaca) hide many of its berries. But when the leaves drop from the deciduous winterberry (I. verticillata), clusters of bright red berries are revealed. There also are both deciduous and evergreen species of rhododendrons and azaleas (Rhododendron spp.).
Shrubs are a highlight during their blossom time, but they may have other features that can add color and diversity throughout the year. Many have attractive foliage in summer and/or fall, some have colorful berries, and others have unusual bark. To add four-season interest to your home landscape, try planting a few of the plants from this list. Plant name is followed by special features and seasons of interest.
Cornus sericea (red-osier dogwood): Flowers, bark; spring, winter
Corylus avellana ‘Contorta’ (Harry Lauder’s walking stick): Leaves, flowers, twisted stems; all seasons
Cotoneaster horizontalis (rockspray cotoneaster): Flowers, fruit, growth habit; all seasons
Hamamelis spp. (witch hazels): Flowers, leaves; winter, spring, fall
Hydrangea quercifolia (oakleaf hydrangea): Leaves, flowers; all seasons
Ilex spp. (hollies): Flowers, foliage, fruit; all seasons
Itea virginica (Virginia sweetspire): Flowers, fall foliage; summer, fall
Lagerstroemia indica (crape myrtle): Flowers, fruits, bark; all seasons
Mahonia spp. (mahonias, Oregon grape hollies): Evergreen leaves, flowers, fruits; all seasons
Pieris spp. (pieris): Flowers, evergreen foliage; all seasons
Rhododendron spp. (rhododendrons and azaleas): Flowers, evergreen leaves; all seasons
Rosa spp. (shrub roses): Flowers, fruits; spring, summer, fall
Vaccinium spp. (blueberries): Flowers, fruits, autumn color; summer, fall
Viburnum spp. (viburnums): Flowers, fruits; spring, fall
There are shrubs for every possible situation in your landscape. For single-specimen accent plants, look to individual shrubs that feature colorful or variegated leaves, large flowers or fruits, and unusual stems or bark. The list at right suggests several excellent accent shrubs. Use specimen or accent plants to mark the entrance to your garden, anchor the end of a perennial border, or add a decorative touch to a deck or patio.
Shrubs are also ideal for creating hedges and screens, and shrub borders make a very effective backdrop for smaller plants in your yard. While conventional hedges generally consist of one species that has been mass planted—privet (Ligustrum spp.) or a compact cultivar of false cypress (Chamaecyparis spp.), for example—plan on using a mix of different shrubs for a screen planting or shrub border. See the Hedges entry for suggestions of shrubs that make effective hedges.
To create an attractive, unified design for a screen or shrub border, select a few different shrubs (both different species and different cultivars of those species), then repeat them along the length of the border to create a rhythm. (See the Garden Design entry for more on selecting and arranging plants.) For year-round interest, select shrubs that have an interesting mix of characteristics—different foliage shapes and colors as well as flowers or fruit that appear at various times of the year. Also mix evergreen and deciduous shrubs. Add vines if you need a tall screen but space is at a premium.
Large shrubs such as witch hazels (Hamamelis spp.) and evergreen viburnums (Viburnum × rhytidophylloides) are good choices for screens and also can be used singly or in groups to frame outdoor spaces, provide privacy, hide unsightly views, and act as a buffer against wind and noise.
A low-growing hedge, such as common boxwood (Buxus sempervirens), can direct traffic around walkways and define borders of flower- and herb beds.
Low-growing shrubs such as rockspray cotoneaster (Cotoneaster horizontalis), shore juniper (Juniperus conferta), or dwarf forms of forsythia are effective groundcovers. Use them to control erosion and ease maintenance on steep banks.
Low-growing Japanese holly (Ilex crenata) and compact abelias (Abelia spp.) make good foreground plants for foundation plantings. Medium and tall shrubs, such as yews (Taxus spp.), are effective background plants for foundation plantings, as well as for perennial beds.
Many medium- and tall-growing shrubs, as well as trees, have compact or dwarf forms, and these often make better landscape plants than their full-size cousins. For example, Chinese juniper (Juniperus chinensis) reaches 70 feet at maturity, but there are many cultivated forms that mature at 3 or 6 feet. When your planting site is small or if you need low-growing plants for a particular spot, look for dwarf and miniature forms of popular shrubs, including many junipers and false cypresses as well as heavenly bamboo (Nandina domestica ‘Nana’) and dwarf mugo pine (Pinus mugo var. mugo). Planting compact and dwarf cultivars ensures you’ll have attractively shaped plants and also greatly reduces pruning maintenance.
Try shrubs with edible fruits, such as blueberries and bush cherries. Plant hollies and viburnums for berries that attract birds and other wildlife.
There are many outstanding native shrubs to choose from that are ideal for both native and conventional landscapes, including sweetspires (Itea spp.), summersweet (Clethra alnifolia), bottlebrush buckeye (Aesculus parviflora), fetterbush (Pieris floribunda), hypericum (Hypericum frondosum), and fothergillas (Fothergilla spp.)
For more ideas on using shrubs in the landscape, see the Hedges, Landscaping, Native Plants, and Rock Gardens entries.
The best shrubs for your garden will depend on where you live. Before you head to the nursery or garden center to buy shrubs, make a list of desired features. What should the shrubs do—form a windscreen, complete your foundation planting, or serve as a specimen? How big can the shrub get, how often will you have time to prune it, and what showy features do you want? You may also want to visit botanical gardens or private gardens in your area to look for outstanding shrubs.
Make a second list of the conditions of your site—soil, water, and exposure. For healthy, vigorous shrubs, match the plant to the site. Since they are important landscape features, select shrubs that are completely hardy in your area. Many gardeners stick to shrubs that are hardy one zone north of where they live to make sure plantings won’t suffer damage during an unusually cold winter. Stick to shrubs hardy in Zone 4, for example, if you live in the northern part of Zone 5.
Combine your two lists to discover what you need to look for when selecting shrubs at the nursery. With your list in hand, you’re ready to buy. Remember that shrubs are a long-term feature of the home landscape. It’s well worth your time and money to seek out and buy good-quality shrubs. Don’t base your selection on price alone. Follow these guidelines when you shop.
Choose healthy plants. Look for plump, firm buds and leaves that are the correct size and color.
Reject shrubs with broken branches or scratched bark, dry or brown leaf margins, or dry rootballs.
Read tags and labels, and don’t buy unlabeled plants. Be sure the flowers, fruit, and form of the plant are what you want. Check if the plant will grow well in the site you have chosen.
Buy bareroot shrubs only when they’re dormant and only if the roots have been kept moist.
Inspect container-grown shrubs, and don’t buy rootbound plants. Many large roots on the outside of the rootball or protruding from drainage holes mean the plant may be stunted by growing in a too-small container.
Select balled-and-burlapped shrubs with firm, well-wrapped rootballs.
The gorgeous flowers of shrubs like forsythia, azaleas, rhododendrons, and shrub roses are a common sight in gardens, but there are many more outstanding flowering shrubs. Try some of the following.
Abeliophyllum distichum (white forsythia)
Caryopteris × clandonensis (bluebeard)
Corylopsis pauciflora (buttercup winter hazel)
Hydrangea arborescens (smooth hydrangea) ‘Annabelle’
Hypericum spp. (hypericums, St. John’s worts)
Itea virginica (sweetspire) ‘Henry’s Garnet’, ‘Little Henry’
Jasminum nudiflorum (winter jasmine)
Philadelphus spp. (mock orange) ‘Avalanche’, ‘Enchantment’, ‘Mont Blanc’
Pieris japonica (lily-of-the-valley bush, Japanese pieris)
Syringa pubescens ssp. patula (lilac) ‘Miss Kim’
Viburnum plicatum f. tomentosum (doublefile viburnum) ‘Mariesii’, ‘Shasta’, ‘Shoshoni’
Weigela spp. (old-fashioned weigela) ‘Wine and Roses’, ‘Spilled Wine’
Plant bareroot shrubs while dormant, from late fall until early spring. Plant container- and field-grown shrubs all year, except when the ground is frozen. If you transplant shrubs from one location to another in your yard, move them while they are dormant. Slide the rootball onto a piece of burlap so it stays intact during the move. For complete instructions on how to plant shrubs, see the Planting entry.
In general, follow the spacing recommendations on plant tags, but to create an effective hedge or screen, plant shrubs slightly closer together than recommended so they will grow together more quickly and will form an unbroken line or group.
Newly planted shrubs require more care than shrubs with well-established roots. Water your shrubs well when you plant or transplant them. Continue to water them each week when less than 1 inch of rain falls, especially in summer and fall. A layer of mulch helps retain water. Keep mulch a couple of inches away from the stems to discourage mice and prevent extra moisture that may cause rot.
Pruning: As your shrubs grow, you’ll need to prune them to control their size, rejuvenate old plants, repair damage and remove pests, and control flowering and fruiting.
Maintain the natural form of your shrubs either by pruning back to outward-facing buds or by removing whole branches. While shearing is faster than naturalistic pruning, it destroys the natural beauty of the plant—and you’ll need to do it often. Learn the natural shape and type of a plant, prune accordingly, and you’ll have to prune far less often. Many plants combine characteristics and may need more than one pruning technique.
Cane growers such as forsythia, heavenly bamboo, and roses are often fountain-shaped. They renew themselves by sending up new canes from the base. Make heading cuts to stimulate lower growth where desired. Thin some branches to maintain an open, uncluttered form. Renew and control cane-growing shrubs by removing older canes at ground level.
Mounding shrubs such as abelias and cotoneasters are generally rounded and have fine or supple branches and small leaves. Mounding shrubs are the easiest type to reduce in size and keep at a given height. You’ll use mostly selective heading cuts to remove unruly and overly long branches, hiding cuts in the shrub interior. Remove up to one-third of the foliage in a year.
Treelike shrubs such as rhododendrons, witch hazels, and viburnums, which have stiff, woody branches, are the most difficult to control in size. Use thinning cuts to remove dead wood, rubbing and crossing branches, and watersprouts to reduce clutter and create definition. Don’t remove more than one-quarter of the greenery in a year.
Prune spring-flowering shrubs soon after they finish blooming in spring and summer-flowering shrubs from late fall until spring bud break. Flower buds form on old wood on spring-flowering shrubs but on new wood for summer-flowering shrubs.
Prune evergreens year-round, except in late summer and early fall. Pruning late in the growing season encourages new growth that may be killed by frosts.
Refer to the illustrations for examples of these pruning strategies. Consult the Pruning and Training entry for basic information on making proper pruning cuts.
Growing tips: Inspect your shrubs often to minimize problems with insects and diseases. Aphids feed on the new growth and flower buds of almost any shrub. Various caterpillars and beetles chew holes in the leaves, while whiteflies feed on leaf undersides. Scales feed on leaves and stems. Shrub diseases range from leaf spots and blights to stem cankers and root rots.
Avoid problems by selecting insect-tolerant or resistant shrubs. Be sure your plants have well-drained soil, sufficient light, and good air circulation to help prevent pest and disease problems before they start. Handpicking, putting out pheromone traps, and spraying insecticidal soap or Bt (Bacillus thuringiensis) are all useful insect controls. For more on pest and disease control, see the Pests and Plant Diseases and Disorders entries.
Heavy ice or snow can sometimes injure dense shrubs, and winter winds can dry out evergreen leaves. For special winter protection, build a temporary structure of boards and burlap. Spray the leaves of evergreen shrubs with an antidesiccant or antitranspirant, a protective coating that keeps the leaves from drying.
Small, yellow leaves or too few flowers or fruits may indicate a nutrient deficiency. A dose of organic fertilizer should help matters, unless it’s a case of the right plant in the wrong place. See the Plant Diseases and Disorders entry for more information.
Propagating: Starting shrubs from seed is an iffy proposition—plant form and flower and leaf color and size can be quite unlike the parent shrub. Making stem or root cuttings or layering are more reliable methods that exactly duplicate the parent plant. Almost any shrub can be propagated using stem cuttings. Forsythia, winter jasmine, and others are easy to propagate by layering. See the Cuttings and Layering entries for particulars.
Pruning strategies. Remove older canes at ground level to renew cane-growing shrubs. Selective heading cuts are best for keeping mounding shrubs looking neat. Thinning cuts are important for removing dead wood and maintaining form of treelike shrubs.
Slugs and garden snails have an appetite for so many fruits, vegetables, and ornamentals that they top many gardeners’ lists of most-hated pests. Slugs and snails are mollusks, not insects, and their soft, muscular bodies secrete slime. Several species, ranging in size from less than 1 inch to more than 4 inches, feed on garden plants.
Slugs and snails need moist surroundings and will hibernate during dry periods. They hide under rocks, garden debris, and mulches during the day. At night, they emerge and chew large ragged holes in leaves. You may find shiny slime trails and damaged plants without ever spotting a slug. For every slug you find, there may be 20 more you don’t see. Damage usually is worst in spring, when soil is moist and plants are young. Follow these guidelines to control slugs and snails.
Create a diverse garden ecosystem to encourage biological controls. Ants, beetle grubs, earwigs, flies, birds, snakes, toads, and turtles prey on slugs.
Don’t plant dense groundcovers or lay mulch near plants you want to protect.
Armed with a flashlight, handpick slugs and snails from plants at night and drop them in a bucket of soapy water.
Set out boards or inverted flowerpots as traps. Check the undersides of traps daily and kill the slugs or snails hidden there.
Sink shallow containers of beer in soil near your plants. Snails and slugs are attracted to beer and will drown after they climb in to drink it.
For serious slug infestations, sprinkle iron phosphate baits (sold at garden centers) around your garden, following label directions. Be sure the bait you buy is an iron phosphate product and not metaldehyde, which is a toxic chemical. Iron phosphate is a natural mineral that eventually breaks down in the soil; it is not toxic to people or pets.
Sprinkle dry soil around the stem bases of your plants.
Make a slug-proof barrier around garden beds by edging them with copper-based strips. Be sure to remove any slugs that are already in the bed when you put up the barrier.
Traditional organic controls include repelling the pests with an oak-leaf mulch and drenching the soil with wormwood tea.
See Antirrhinum
Organic gardeners live by a basic principle: Feed the soil, and let the soil feed the plants. Feeding soil with organic matter, from compost to grass clippings, is the key to successful organic gardening. Of course, it’s not the soil itself that consumes the organic matter, it’s the living organisms in the soil—animals, insects, bacteria, fungi, and other organisms—that do. In the process, they break down the organic material into nutrients that can be taken up by plant roots.
Few gardeners start out with balanced soil—that is, well-aerated soil that is rich in organic matter—that’s ideal for gardening. There are many reasons why the soil in your yard and garden could be out of balance. Surface soil is often disturbed—or even removed—during construction, and nothing is done to restore the soil afterward. Your soil may be compacted, which means it has too little space for air and water, because of repeated walking or driving on it with equipment such as lawn tractors. Here are some other reasons your soil may need some TLC before it is ready for planting.
Your soil’s natural characteristics may not be favorable for gardening. For example, you may have such sandy soil that it can’t hold sufficient water and nutrients to support vigorous plant growth. Or your soil’s pH may be so acidic that many kinds of plants won’t thrive.
Unless you’re a longtime organic gardener, the soil may be depleted of nutrients because no one has fed it with organic matter for many years.
If you’ve used chemical fertilizers, the soil microorganisms that play an important role in maintaining natural fertility may have died off.
A good first step in the process of improving your soil is to make some tests that will help you learn about its characteristics. After testing, you’ll know what problems your soil has, and you can take steps to remedy them. Your soil improvement process will include adding organic matter and possibly other soil amendments. While you work on improving your soil, you may want to use organic fertilizers to boost plant performance.
Sand, silt, and clay. Tiny fragments of rock or minerals that make up nearly half the material in the soil. They are distinguished from one another by size. Sand particles are from 0.05 to 2.0 millimeters in diameter, silt particles are from 0.002 to 0.05 millimeter, and clay particles are less than 0.002 millimeter in diameter.
Soil texture. The relative proportions of sand, silt, and clay in the soil.
Soil structure. The arrangement of soil particles in the soil.
Loam. Soil that has moderate amounts of sand, silt, and clay. Loam soils are generally considered the best garden soils.
Soil pH. A measurement of the acidity or alkalinity of the soil.
Organic matter. Various forms of living or dead plant and animal material.
Microorganisms. Animals and plants that are too small to be seen clearly without the use of a microscope.
Decay cycle. The changes that occur as plants grow, die, and break down in the soil. The action of soil animals and microorganisms break down plant tissues to release nutrients that new plants then take up to fuel their growth and development.
Humus. A dark-colored, stable form of organic matter that remains after most of the plant and animal residues in it have decomposed. When soil animals and microbes digest organic matter, such as chopped leaves or weeds, humus is the end product.
Erosion. The wearing away of soil by running water, wind, ice, or other geological forces. Erosion can be accelerated by the activity of people or animals.
Soil is much more than just dirt. It’s an intricate, fascinating mix of fine rock particles, water, air, organic matter, microorganisms, and other animals. Surprisingly, in ideal garden soil only about 45 percent of it consists of minerals, which we classify by size as sand, silt, and clay. Half the volume of good garden soil is pore space filled with either water or air—large pores hold air, while smaller pores hold water and dissolved nutrients. Ideally, the remaining 5 percent is organic matter.
The size differences between the three types of soil particles—sand, silt, or clay—are very small yet highly important. The relative proportion of these tiny rock fragments—referred to as soil texture—influences how well soil holds water and air, and also how fertile it is.
Texture differences: The spaces between sand particles are comparatively large, so they do not tend to granulate, or stick together. Thus, sandy soils have few small pores and often do not hold enough water and/or dissolved nutrients to support the growth of many kinds of plants.
Clay soils are rich in very tiny particles that are attracted to each other when wet. While these clay particles can be interspersed with tiny pore spaces that can hold large reserves of water and dissolved nutrients, too much clay also can create problems. When clay particles dry, they stick together and form a hard layer with no pore spaces. When a hard layer forms at the soil surface (this is called crusting), water cannot penetrate easily. A clay layer deeper in the soil can form a hardpan that impedes water drainage.
Soil with a good balance of sand, silt, and clay particles is called loam, and it is often ideal for gardening, because it forms lots of large and small pore spaces and does not tend to crust over like clay soil does.
It takes a huge effort to change soil texture. For example, to have a beneficial effort on clayey soil in a 20- by 50-foot garden bed, you’d have to add about 3 to 5 tons of sand to the top 6 inches of soil.
Soil structure: Fortunately, there are steps you can take to improve another important characteristic, soil structure—the way in which soil particles clump together. A soil’s structure determines how well it retains water and how quickly water drains through the soil, how much air is available in the soil, and how easily nutrients are released for uptake by plant roots.
Ideal garden soil is friable—the soil particles are held together in clumps called aggregates that can easily break apart. Such loose clumping allows water to drain through, and oxygen and carbon dioxide can easily move from the air above into the spaces below. Pore space can vary from 30 to 50 percent of soil volume.
Many factors contribute to the creation of soil structure. Soil water freezes and thaws, plant roots grow and die, earthworms move through the soil, and bacteria and other microorganisms secrete substances that help aggregates form. Soil structure is also affected by soil pH, the amount of humus in the soil, and the combination of minerals in the soil. The best way to improve soil structure, and thus the water-holding capacity and aeration of your soil, is to add organic matter—lots of it. (You’ll learn more about how to add organic matter to your soil later in this entry.)
It’s important to remember that soil structure is very easy to destroy. Tilling excessively, walking on soil, or working soils that are too wet or too dry (see “Is It Ready to Work?” sidebar for tips on determining when your soil is ready to work) can break apart soil aggregates, thus destroying soil structure, and the damage is not easily undone.
Why is there air in the soil? One reason is that many beneficial soil organisms cannot live without oxygen. Gaseous nitrogen, another component of soil air, is a raw material for nitrogen-fixing bacteria that manufacture protein materials. These are later broken down to yield nitrogen compounds that can be absorbed by plant roots. Plant roots also “breathe” and need good air exchange between soil air and the atmosphere for proper development. If soil doesn’t drain well (meaning it has too few large pores), water occupies all the soil pore space. This suffocates the plants because their roots cannot get the air they need.
Plant roots absorb water from the small soil pores where it’s stored, and that water then travels through the plant’s conduction system (like a system of pipes) to leaves and stems, where it serves as a nutrient, a coolant, and as an essential part of all plant cells. Water is also the carrier for mineral nutrients, such as nitrogen and potassium, that plants need for growth and development.
Soil pore spaces should vary in size and be evenly distributed. Soil with sufficient organic matter will have this quality. Walking on the soil or driving yard and garden equipment over it can cause pore spaces to collapse.
A soil summary. Soil that has good structure is about half solids and half open space (pores). Surprisingly, the all-important organic matter component of soil is its smallest component by volume.
Although they are only a minute portion of the soil by weight and volume, the living organisms in soil play a vital role. Soil microorganisms power the decay cycle—nature’s perfect system for recycling organic matter and maintaining healthy soils. Soil microorganisms include nematodes, protozoa, fungi, bacteria, and actinomycetes (threadlike bacteria). These microorganisms, along with mites, insects, millipedes, and earthworms, break down dead and dying plant tissues into simpler components. Their waste products, in addition to the bodies of the organisms themselves, become part of the soil’s organic matter content. As the cycle progresses, complex proteins are converted to simple nitrogen compounds that plant roots can absorb, and minerals such as potassium and phosphorus are changed into soluble compounds.
Plant roots secrete substances that encourage a variety of beneficial microorganisms, and they also benefit from a symbiotic relationship with mycorrhizal fungi: These special fungi obtain carbohydrates and sugars from the plant’s roots, and the plant uses the mycelium (masses of threadlike cells) produced by the fungi to absorb soil water and dissolved nutrients.
Earthworms serve as natural “tillers” and soil conditioners, moving organic matter around in the soil. Many soil-dwelling insects are parasites and predators of insects that harm crop plants. And soil animals, including the much-maligned mole, also help improve soil aeration and eat some harmful insects.
Ultimately, soil microorganisms convert plant material to humus. Humus is important because it has a complicated (microscopic) structure with lots of tiny openings where soil microbes can thrive and that help store water in the soil. Humus also has a chemical makeup that allows it to “hang on” to many important nutrients such as calcium, potassium, magnesium, and iron so they won’t be lost by leaching (water moving quickly through the soil).
One question home gardeners frequently ask is, “Should I add anything to my soil this spring?” While adding organic matter is always the best answer to that question, you can get a more detailed answer by investigating your soil to learn about its structure and content.
There are several simple tests you can do yourself to learn about your soil’s structure, drainage, and earthworm activity (earthworms are a key indicator of soil health). You can also submit soil samples from your yard for soil analysis—see below for more on collecting and using soil test results.
An easy way to learn about your soil’s condition is to try simple tests that rely not on precise chemical analysis but rather on your observations of the soil. With these tests, there is little or no cost and no waiting for results.
The squeeze test: This test helps you determine soil texture. Do this test 2 or 3 days after a rainy spell. Take a loose ball of soil about the size of a Ping-Pong ball in the palm of your hand. Gently squeeze it between the ball of your thumb and the lower outside edge of your index finger and think about what it feels like. Sand feels gritty, silt feels like moist talcum powder, and clay feels slippery.
Squeeze the ball in your hand, and release. If it crumbles, it has a reasonably balanced texture. If the soil ball can hold its shape, it has a substantial percentage of clay. If you can roll it into a sausage shape or press it into a thick ribbon, it has even more clay.
Run the palm of your other hand firmly over the handful of soil. If you see scratch marks on the surface of the soil, there is a sizable proportion of sand present. If the soil feels greasy, this indicates silt.
The perc test: This test is an easy way to assess water drainage through your soil. Dig a hole about 1 foot across and 1 foot deep. Fill the hole with water and let it drain. As soon as the water has drained completely, fill it again. This time, keep track of how long it takes for the hole to drain. If it takes more than 8 hours, you have a drainage problem that needs attention.
The watering test: A variation on the perc test will tell you if your soil drains too rapidly. Start by watering a small area of your lawn or garden bed very thoroughly. Two days later, dig a small hole 6 inches deep where you watered. If the soil already is dry to the bottom of the hole, your soil likely doesn’t retain enough water for good plant growth.
Another way to monitor soil moisture is to use a manual or automatic moisture sensor. These are small, electronic devices that measure available water in the soil, letting you know how long water levels are adequate for your plants’ needs. If a meter indicates that the soil needs rewatering only a few days after you’ve watered thoroughly or after a soaking rain, then you need to improve the soil’s water-retention capacity.
The undercover test: The best way to learn about some aspects of your soil is to get right down into it. If you plan to plant a new tree or shrub, check out your soil as you prepare the hole. Your new plant will benefit from the extra-large planting hole, and you’ll get valuable information about what’s happening beneath the soil surface.
Dig a hole at least 2 feet across so you can get a view down into it and, ideally, dig down 2 feet deep as well. Pile soil on a tarp as you dig, so you can neatly refill the hole when you’re done. Then observe your soil closely. Abundant earthworms and other soil organisms, as well as healthy plant roots and a dark topsoil layer indicate healthy soil. If you can’t find many earthworms or other organisms, if roots are stunted or malformed, and if the topsoil layer is thin or nonexistent, your soil strongly needs improving.
If you have your soil tested by a soil-testing laboratory, the test results will include a nutrient analysis and also a measurement of your soil’s pH. However, at times you may want to test pH only. For example, if you plan to plant blueberries, which require acid soil, you may want to quickly check pH at several sites to see if the soil pH needs adjusting. For more information about pH testing and changing soil pH, see the pH entry.
An indirect way to find out about nutrient levels in your soil is to analyze the content of the plants growing in it. Plant analysis is not a do-it-yourself test. Many extension offices and some private labs will analyze samples of leaf tissue for nutrient content. This type of testing may provide more accurate results for certain nutrients, including nitrogen, than soil analysis does. The labs analyze the nutrient content in the samples and compare the readings with compiled research data that show the normal range of nutrients required for optimal growth of that species. Based on that comparison, they make recommendations for treatment.
If you decide to use the extension office or a privately run soil-testing laboratory to test your soil, you’ll need to collect a soil sample. Contact your local extension office for a soil test kit or see Resources for a Web site that lists soil-testing firms. Both will offer recommendations on soil improvement based on the results of their tests.
You may want to collect many samples from around your yard and combine them to submit for a single test and report. Or you may want to prepare separate samples from your vegetable garden soil, your lawn, and an area where you hope to create a flower border, for example. However, you’ll have to pay three times as much to get the three separate sets of recommendations.
Follow these steps to prepare a sample that will accurately reflect the content of your soil.
1.Scrape away any surface litter or plant growth from a small area of soil. Use a soil probe to cut a core of soil, or dig a hole with a stainless steel trowel or other tool (if you don’t have stainless steel tools, use a large stainless steel spoon) and collect a slice of soil from the side of the hole. For cultivated areas, collect a core or slice to a depth of 6 inches. For lawns, collect your samples only from the top 4 inches of soil.
2.Repeat the sampling procedures at 10 to 15 different locations around your yard or the particular area you are sampling.
3.Mix the soil cores or slices in a clean plastic or stainless steel container.
4.Place some of the mixed sample in a plastic container or bag, and put it in the bag supplied by the soil-testing laboratory for shipment.
Don’t touch the sample with soft steel, galvanized, or brass tools or with your bare skin. The content of some minerals in soil is so small that minerals picked up from these metals or your skin could throw off test results.
You’ll send your sample, along with an information sheet concerning your soil’s history and your future gardening plans, to the testing laboratory by mail. Be sure to write on the information form that you want recommendations for organic soil amendments.
After analyzing your soil, the test lab will send you a report on the results of their analysis and recommendations for improving your soil.
Test results may include soil pH, organic matter content, and content of calcium, magnesium, nitrogen, phosphorus, potassium, sodium, sulfur, and trace minerals.
Soil labs make recommendations based on results of their research programs on plant responses to additions of mineral amendments. When you send in your sample, be sure to ask clearly for recommendations for organic amendments.
Keep in mind that making the recommendations is an imprecise science because the researchers must try to relate the data from the research soils they study to your individual soil. However, all soils are different. They do not all respond equally to applications of minerals or organic materials. (Typically, soil fertility studies are performed on soils that have low organic matter content. Analysis of such low-organic-matter soils may be more accurate because organic matter makes the soil more biologically diverse and complex.)
There are no overnight or even single-season organic solutions for an imbalanced soil. Unlike gardeners who rely on soluble synthetic chemical fertilizers to keep their plants green and growing, organic gardeners boost the soil’s natural fertility through a 2-, 3-, or 4-year program that results in a fertile, rich soil. Fortunately, your plants don’t have to suffer during the soil-building years: You can provide organic fertilizers as a supplement to meet your plants’ needs for nutrients.
Organic matter is almost like a miracle cure for soil problems (but remember, it’s a slow-acting one). The benefits of organic matter include:
Improving soil structure and biological activity
Stimulating the growth and reproductive capacity of the bacteria and other microorganisms that help create a vital and productive soil
Increasing the water- and nutrient-holding capacity of the soil
Alleviating mineral deficiencies and buffering soil pH
There is a wide range of organic materials available to gardeners. The best of these is compost—a mixture of decayed organic materials. To learn how to make and use compost, read the Compost entry. Other good organic materials include chopped leaves, straw, grass clippings, and aged manure.
How to add organic matter: You can add organic matter by digging or tilling it into the surface of the soil, by planting cover or green manure crops, or simply by adding mulches and allowing them to break down over time. See the Cover Crops and Mulch entries for more information on these methods.
It’s relatively easy to increase the humus content of vegetable gardens because they are usually cleared of plants every year. But how do you increase the organic material in a perennial garden or under an existing lawn? Or around trees and shrubs? Wherever you have existing plants, including lawn grass, shrubs, or perennials, you can spread compost or other decayed organic material on the surface. In a few months, the earthworms and other soil organisms will have begun to work that organic material down into the soil. The other method for flower gardens and around trees and shrubs is to use some kind of organic mulch—chopped leaves, for example, or a thin layer of compost under conventional mulch—and let it break down naturally, giving the soil an organic material boost as it does. You can do this at any convenient time of year.
How much to add: Five percent organic matter is a good goal to strive for in your soil. One inch of compost or other fine-textured organic material spread over the soil surface equals about 5 percent of the volume of the first foot of soil. Thus, as a rule of thumb, if you add about 1 inch of fine organic matter to a garden every year, you will gradually increase that soil’s organic matter content to a desirable level. If you use a bulkier material such as chopped leaves or straw, you will have to apply a thicker layer, because there is less actual matter per volume. A 4-inch layer of bulky organic material is equivalent to a 1-inch layer of fine material.
In the South, it’s more difficult to maintain organic matter content in soil. Microbial populations grow faster (and so “eat” more organic matter) in warmer temperatures. Organic material can break down twice as fast in hot southern soils as it does in cooler northern soils. Organic matter also breaks down more quickly in sandy soil than it does in loam or clay.
Fresh versus dry: On the average, fresh organic matter—such as grass clippings, kitchen waste, and green weeds—worked into the soil will be 50 percent decayed in just 2 months. The material will be 75 percent decayed after 4 months, and about 87 percent decayed after 6 months.
Dry materials decompose more slowly than moist materials. For example, if you dig chopped dried leaves into your garden, it may take 4 or 5 months for them to be halfway along the path of transformation to humus.
The decay process works best if there is a constant supply of food for the soil microorganisms that act as the decay “machine.” In areas where you’ve incorporated partially decayed material, it’s a good idea to spread some dry organic matter as a surface mulch. The mulch serves two functions. It protects the decomposing organic matter from excessive heat, which can cause some organic compounds to volatilize (turn from a solid state into a gas) and be lost. It also provides a longer-term food source for the soil microorganisms that are stimulated by the dug-in organic matter.
The rule of mulch: There is one cardinal rule in your efforts to increase the organic content of your soil. Once you’ve added whatever material your soil needs, there should not be 1 square inch of bare soil left anywhere on your property. It should be covered with grass, a groundcover, plants, or mulch. Bare soil loses humus much faster than covered soil because the nutrients created by the decomposition of the organic matter are leached away more readily. In addition, the impact of raindrops on bare soil can destroy the loose soil structure you have worked to obtain. Covered soil is also much less prone to surface erosion by wind or water.
Two of the most common problems gardeners face are soils that are high in clay and soils that don’t drain well.
Clay soils: If you have heavy clay soil that is low in organic matter, you will have to add considerable amounts of organic material and energy to make that soil as loose and friable as you can. Digging it deeply into the soil—to a spade’s depth, or by double-digging—is your best option. Some gardeners will add sand along with the organic material to heavy clay soils in beds where they want to grow root crops or flower bulbs. A lot of sand is required to make a significant difference, though. Adding small amounts of sand may actually cause your soil to harden, worsening its condition (think concrete). To boost the sand component of the top 6 to 8 inches of the soil by 5 to 10 percent, you will need about 3 to 5 tons per 1,000 square feet of garden. If you have a close and convenient source of sand, it may be worth the effort to spread and till in the sand. However, adding sand alone will not remedy problems with heavy clay. Using cover or green manure crops and incorporating organic matter are the best long-term solutions.
Poorly drained soils: If your soil tests and observations have alerted you to a drainage problem in your yard, you have three options. Your first option could be to accept the wet spot and create a small bog garden. If you have other plans for the site, you’ll have to find a way to improve drainage.
The drainage problem may be due to a hardpan somewhere in the top 2 feet of soil. You may be able to break up the compaction layer by double-digging. If the layer is deeper than you can reach by double-digging, try planting deep-rooted sweet clover in spring and allow it to grow for two full growing seasons. The roots may penetrate the deep hardpan and naturally create better drainage.
Another way to sidestep a drainage problem is to create a raised bed in the wet area. You’ll have to bring in extra topsoil and build up the bed, essentially creating a layer of soil with good drainage for plants to grow in above the poorly drained area.
Lastly, you can install a drainage system, but this is a project for which you’ll probably need to hire a professional landscaper.
Tilling or digging the soil when it is either too wet or too dry is disastrous for soil structure. Wet soils will form large clumps when tilled. The clumps will dry hard and solid, without the many tiny pores that hold water and air in the soil. Without air, root growth suffers. Cultivating soil that’s too wet can also cause water to run off or sit in puddles on the surface rather than percolate down into the root zone. If your soil is too wet, let it dry before planting. Pick up a handful of soil and squeeze it. If it crumbles into smaller, light-textured pieces, it’s perfect for planting. But if it forms a muddy ball, the soil is too wet to be worked. Wait a few days, and test again to see if it has dried out. Dry soils can turn to fine dust when tilled, which also destroys the structure you’ve worked so hard to build. If a handful of soil crumbles immediately to dust, water the site thoroughly and wait a day before testing it again.
Some garden suppliers sell products purported to enrich and/or boost populations of soil microbes. Some of these products list vitamins and enzymes as their active ingredients, while others contain mycorrhizal fungi and other microorganisms. Soil that has been amended with compost and other organic matter probably already contains a diverse population of microorganisms. However, if you’re a gardener who’s switching to organic methods from chemical methods, or if you’ve inherited a garden that’s been treated with pesticides, you may have soils with very low biological activity. You may want to experiment by adding a microbial booster product to your soil and/or compost pile. Some of these cultures are in a dry, dormant, powdered form. After you spread this material over your soil or into a compost pile, the microbes become activated and biological activity accelerates. Keep in mind that you must keep adding sufficient organic matter to feed the increased populations of soil microbes, or you won’t get any lasting benefit from your investment
Encouraging earthworms: If your earthworm count is low, don’t despair. Once you provide more organic material to feed them, they will usually return. Earthworm egg casings may lay dormant as deep as 20 feet in the soil for as long as 20 years.
Dry or granular, fast-acting chemical fertilizers can repel earthworms when they dissolve in soil water and leach down into the soil. Earthworms are highly sensitive to changes in the physical and chemical environment and will avoid the salty conditions created by the chemical fertilizers. If you are making the transition from chemical fertilizers to organic soil amendments and fertilizers, have patience. As your soil reaches a healthy balance, you will see more earthworm activity.
Several organic soil amendments are available to help correct specific pH and mineral imbalances. In most cases, it’s wisest to add these amendments only according to recommendations from soil tests or plant analyses. If you add too much of a natural mineral supplement such as rock phosphate, you can create an excess of a particular nutrient. The excess may damage plants or may interfere with uptake of some other nutrients. For more information on soil amendments, see the Fertilizers entry.
To many gardeners, starting a new garden bed means using a rotary tiller. While a tiller is a powerful and helpful tool, tilling is not the best way to work the soil. One good alternative is to start new garden beds by building them from the ground up, a method known as lasagna gardening. To learn more about this, turn to the Raised Bed Gardening entry.
Some vegetable gardeners use their rotary tillers several times during the season. They may till in a green manure crop in early spring, and then till again a few weeks later to make a fine seedbed for planting. During the season, they may get out a smaller tiller for weed control, then till the garden under again in fall. While tillers seem convenient, their use gets costlier all the time as fuel prices increase, plus there’s the environmental cost for the carbon dioxide they produce and the damage they do to the living organisms in your soil.
Double-digging. Double-digging creates a deep, loose bed that’s excellent for deep-rooted crops such as carrots and parsnips and for long-term plantings such as a perennial garden. Single digging is more than adequate for many veggies, herbs, and annual flowers. Building a raised bed on top of a single-dug area offers the same benefits as double-digging.
The loss of topsoil through erosion isn’t just a problem on farms and at construction sites. Erosion can happen in our own front and back yards. Take these steps to minimize soil erosion around your home.
•On slopes, build terraced garden beds, or at the very least, be sure your garden rows run across the slope, not up and down.
•Don’t leave sloping areas unplanted. Plant groundcovers, vines, or other plants with spreading roots and top growth that will hold soil in place.
•Mulch permanent pathways with stone or a thick layer of organic mulch, or plant a durable groundcover or lawn grass.
•In fall and winter, mulch bare vegetable or flowerbeds, or plant a cover crop to prevent wind or water erosion.
•Keep areas cleared for construction well mulched with straw. Try to minimize the use of heavy equipment. Soil compacted by machinery cannot absorb water well; the runoff will carry valuable soil with it.
Digging a garden bed takes considerable time and effort, but it’s work well rewarded by more-vigorous, higher-yielding plants. Plants growing in deeply prepared soil also have deeper roots and are thus more drought tolerant.
The traditional technique for preparing a perennial garden or improving drainage on a poorly drained site is to double-dig. This process improves the structure and fertility of the top 2 feet of the soil.
To double-dig a new bed, start by marking off the edges of the bed and watering deeply several days before you plan to dig. Then follow the steps below.
1.Strip off weeds or sod. Discard roots of perennial weeds in the trash. Turn sod strips upside down on the compost pile, or use them to patch existing lawn.
2.Dig a 1-foot-wide, 1-foot-deep trench along one edge of your site. Put the soil into a wheelbarrow or onto a tarp.
3.Loosen the soil at the bottom of your trench by inserting a garden fork and wiggling or twisting it around. Top it with a 1- to 2-inch layer of organic matter.
4.Dig a second 1- by 1-foot trench next to the first, placing the soil on top of the layer of organic matter in the first trench. Then loosen the soil beneath it and add another layer of organic matter.
5.Continue systematically down the bed, digging trenches and loosening subsoil. When you get to the end, use the reserved soil from the first trench to fill the final one.
6.Spread compost or other organic material over the entire bed, then use a spading fork to work it into the top 4 to 6 inches of soil. The amount of organic material you add can vary, but 2 to 3 inches is adequate.
When you double-dig, lavish most of the organic material on the topsoil. Add only small amounts of compost or chopped leaves to the lower soil layer because the rate of decay is much slower in the second 6 inches of soil than it is in the top 6 inches. Double-digging your beds will raise them about 3 to 4 inches because it thoroughly loosens and aerates the soil.
Double-digging is hard work. If you have back problems, it’s probably best not to double-dig your garden. And if you’ve never tried double-digging a bed before, start small. Try working a 3- by 3-foot bed, and build up from there. And remember, you don’t have to dig an entire bed in one stint—you can spread out the work over several days or a few weekends.
Another method for improving soil, that’s less work than double-digging, is single-digging. In this case, you loosen the soil to a shovel’s depth—about 6 inches—and incorporate organic matter in that portion of the soil. Yet another option is to single-dig, then create a raised bed on top of the prepared soil.
Tilling or hand-digging, no matter how carefully done, has a major impact on soil microorganisms. When you turn the soil, you add an enormous amount of oxygen to it. This creates an environment primed for an explosion of microbial activity. In most soils, more than 80 percent of the aerobic bacteria are present in the top 6 inches; more than 60 percent are in the top 3 to 4 inches. If you add organic matter as you till, you supply fuel for the population explosion, and your soil will remain in balance. On the other hand, if you till repeatedly, thus increasing the microbial population, you’ll speed the decomposition of your soil’s organic reserves and soil organic matter levels will decrease.
So for your soil’s and plants’ sakes, don’t use a tiller unless you really need it. Instead, hire a neighbor’s teenage daughter or son to dig a new garden bed if you can’t do it yourself. Once a bed is dug, keep the soil loose and healthy by relying on mulch to reduce weed problems and conserve soil moisture, by avoiding walking on beds, and by cultivating shallowly when weeds are small.
Goldenrod. Summer- and fall-blooming perennials.
Description: There are many species of our native goldenrod that are fine for naturalizing, and some of their cultivars have become stars of the late-summer garden.
Solidago canadensis, Canada goldenrod, is the wide-ranging North American wildflower that turns fields and roadsides golden-yellow in late summer. S. rugosa ‘Fireworks’ (‘Fireworks’ rough goldenrod) bears a profusion of arching sprays of bright yellow blooms over 2½- to 3½-foot upright, leafy stems. S. sphacelata ‘Golden Fleece’ (‘Golden Fleece’ autumn goldenrod) is just 1 foot tall, perfect for the front of the border. It bears abundant sprays of golden yellow blooms over deep green, paddle-shaped leaves. Zones 4–9.
Hybrid goldenrods are also excellent garden plants. Hybrid goldenrods bear tiny yellow and gold flowers in showy 4- to 12-inch clusters over upright to vase-shaped clumps. Elongated leaves spiral up the stiff, 1- to 3-foot stems. One of the best is ‘Crown of Rays’. Zones 3–8.
Several species once included in the genus Solidago have been reclassified as Euthamia and dubbed “goldentops” rather than goldenrods. Whatever the name, these attractive summer and fall bloomers make handsome companions for late-blooming asters in naturalistic plantings and wildflower meadows where their bright flower sprays welcome all manner of pollinators.
How to grow: Plant or divide in spring or fall in a sunny or lightly shaded spot. Goldenrods do best in average, moist, well-drained soil, though most tolerate fairly dry soil. Divide every 3 years to keep in bounds. Goldenrods can self-sow; keep an eye out for seedlings and remove them where they’re not wanted.
Landscape uses: Grow goldenrods in small clumps in borders; mass in fields and meadow gardens. Combine with asters, other fall-blooming perennials, and ornamental grasses. Remember, it’s ragweed that causes hay fever, not goldenrod.
Spinacia oleracea
Chenopodiaceae
Spinach is one of the most satisfying cool-weather crops to grow, producing large yields of vitamin-rich, dark green leaves that are excellent for salads and for cooking. Since both hot weather and long days trigger spinach to bolt (send up a seedstalk) quickly, the secret to success with this crop is to start sowing seeds as soon as possible in spring, to make small, frequent plantings during late spring and summer, and to concentrate on fall as the season for the main crop.
Planting: Spinach does best when growing in moist, nitrogen-rich soil. Spinach plants form a deep taproot; for best growth, loosen the soil at least 1 foot deep before planting.
Sow spinach seed as early as 6 weeks before the last frost or as soon as you can work the soil. Prepare the soil the previous autumn, and you can drop the seeds in barely thawed ground. In areas with a long, cool spring, make successive plantings every 10 days until mid-May.
In warm climates, plant spinach in the shade of tall crops such as corn or beans. The young plants will be spared the hottest sun and be ready for harvest in fall or winter. Using cold frames or heavyweight row covers, you can grow spinach all winter in many parts of the country. In colder regions, try planting in fall (October) and protecting the young plants through winter for a spring harvest. In regions where the soil doesn’t freeze, try planting spinach in February for a March harvest.
Spinach seed doesn’t store well, so buy fresh seeds every year. Sow them ½ inch deep and 2 inches apart in beds or rows. If the weather isn’t extremely cold, seeds will germinate in 5 to 9 days. Spinach produces beautifully in cool fall conditions, but it’s tricky to persuade the seed to germinate in the hot conditions of late summer. Sow seed heavily, because the germination rate drops to about 50 percent in warm weather, and water the seedbeds frequently—even twice a day—because watering helps to cool the soil.
Growing guidelines: Overcrowding stunts growth and encourages plants to go to seed. To avoid crowding, thin seedlings to 4 to 6 inches apart once they have at least two true leaves. Fertilize with compost tea or fish emulsion when the plants have four true leaves. (See the Compost entry for instructions for making compost tea.)
Since cultivating or hand-pulling weeds can harm spinach roots, it’s best to spread a light mulch of hay, straw, or grass clippings along the rows to suppress weeds instead. Water stress will encourage plants to bolt, so provide enough water to keep the soil moist but not soggy. Cover the crop with shade cloth if the temperature goes above 80°F.
Problems: Since most spinach grows in very cool weather, pests are usually not a problem. Leaf miner larvae can burrow inside leaves and produce tan patches. Prevent leaf miner problems by keeping your crop covered with floating row cover. For unprotected plants, remove and destroy affected leaves to prevent adult flies from multiplying and further affecting the crop. For information on controlling aphids, cutworms, and cabbage loopers, see The Top 10 Garden Insect Pests. Slugs also feed on spinach; see the Slugs and Snails entry for controls.
Spinach blight, a virus spread by aphids, causes yellow leaves and stunted plants. Downy mildew, which appears as yellow spots on leaf surfaces and mold on the undersides, occurs during very wet weather. Reduce the spread of disease spores by not working around wet plants. Avoid both of these diseases by planting resistant cultivars.
Harvesting: In 6 to 8 weeks, you can start harvesting from any plant that has at least six leaves 3 to 4 inches long. Carefully cutting the outside leaves will extend the plants’ productivity, particularly with fall crops. Harvest the entire crop at the first sign of bolting by using a sharp knife to cut through the main stem just below the soil surface.
Where high temperatures make spinach growing difficult, consider these heat-tolerant alternatives to add spinach-like flavor to your salads.
Vegetable amaranth (Amaranthus tricolor)
Orach (Atriplex hortensis)
Tatsoi (Brassica rapa var. narinosa)
New Zealand spinach (Tetragonia tetragonioides)
Malabar spinach (Basella rubra)
Spirea, bridal wreath. Deciduous, spring-blooming shrubs.
Description: Spiraea japonica, Japanese spirea, is a 6-foot shrub that spreads to 5 feet. Plants bear toothed leaves and flat 4- to 6-inch-wide clusters of lacy pink or white flowers in summer. Cultivars of this species are much more common in gardens than the species. ‘Goldflame’, to 3 feet tall and wide, features chartreuse leaves. ‘Little Princess’ is just under 2 feet and spreads 3 feet. The variety S. japonica var. bullata is a 12- to 15-inch-tall dwarf shrub with blue-green, crinkled leaves and 1½- to 3-inch rosy red flower clusters in summer; its size makes it excellent in rock gardens or as a ground-cover. The hybrid S. × bumalda grows to 2 feet tall and spreads to 3 feet. Zones 4–9.
S. prunifolia, bridal wreath spirea, has an upright, rounded form, growing to about 10 feet. Its slender, oval, shiny dark green leaves are 1 to 2 inches long. The flowers are pure white and double, blooming in profusion along each branch in spring. For fall color, bridal wreath is one of the most reliable spireas, usually turning a soft orange-red. Zones 5–8.
S. × vanhouttei, Vanhoutte spirea, has an arching form that’s narrow and bare at the base, reaching 6 to 8 feet tall and 10 to 12 feet wide. It bears white flowers in flat clusters along the branches in late spring, and blue-green, ¾- to 1¾-inch, fine-textured foliage. Zones 3–8.
How to grow: All spireas need full sun and good drainage. Promote vigorous growth by removing a third of the oldest branches to a few inches above ground level after bloom time. If drastic renewal is needed, cut the entire shrub in this way.
Landscape uses: Because of their compact form, cultivars of Japanese spirea make fine foundation plants. All spireas are useful for massed plantings, specimens, and borders.
See Picea
Cucurbita spp.
Cucurbitaceae
From acorn squash to zucchini, this group of vegetables has a delightful range of shapes, sizes, colors, and flavors. These frost-tender plants need warm weather, lots of sun, and plenty of room.
Types: Squash come in two main types: summer squash and winter squash. While there’s not much difference among the flavors and textures of summer squashes, winter squashes offer a wide array of flavors.
Summer squash (Cucurbita pepo) produces prolifically from early summer until the first frost. This group includes both green and yellow zucchini, most yellow crookneck and straightneck squash, and scallop (or pattypan) squash. Most summer squash are ready to pick 60 to 70 days after planting, but some reach harvestable size in 50 days. You can use them raw for salads and dips or cook them in a wide variety of ways, including squash “french fries” and such classics as zucchini bread.
Summer squash blossoms, picked just before they open, are delicious in soups and stews, or try them sautéed, stuffed, or dipped in batter and fried. (You’ll want to use mostly male flowers for this purpose, though, and leave the female flowers to produce fruit. See the illustration to distinguish male from female flowers.) Summer squash keep for only a week or so in the refrigerator, so you’ll probably want to freeze most of the crop.
Winter squash (C. maxima, C. mixta, C. moschata, and C. pepo) is a broad category that includes butternut, acorn, delicata, Hubbard, banana, buttercup (or turban), and spaghetti squash. Pumpkins are also in this group, but their flesh is often less sweet than other winter squash. Most winter squash take 75 to 120 days to mature.
Steam the young fruits, or harvest and bake the squash when they’re fully mature. Dry and roast the seeds. Winter squash are even more nutritious than their summer kin, but the sprawling vines, which can grow 10 to 20 feet long, require more space. If you have only a small garden, try one of the bush or semibush cultivars.
Butternuts produce fruits up to 1 foot long with tan skins and orange flesh. Acorn squash have dark green to yellow fruits that are round and usually furrowed; they generally weigh 1 to 2 pounds. Acorns don’t store as well as most winter squash, but they are very productive.
Delicata squash can take more than 100 days to mature, but the wait is worth it; the wide-spreading vines produce wonderfully sweet fruit. Hubbards are best for storing, but standard cultivars can weigh up to 30 pounds, which is a lot of squash to eat. Pink-skinned banana squash can grow up to 75 pounds. Buttercup, or turban, squash have a sumptuous flavor that makes them a winter squash favorite.
Planting: These sun lovers are sensitive to cold, though winter squash tolerate light shade and cooler nighttime temperatures better than summer squash.
Both types of squash are heavy feeders and need a light and well-drained but moisture-retentive soil. You can give them exactly what they need by planting them in specially prepared hills. See the Melon entry for details on creating supercharged planting hills. Space the hills 3 feet apart for summer squash; vining winter squash need 6 to 8 feet between hills.
Summer squash can cross-pollinate with various cultivars of both summer and winter squash, as well as with several types of pumpkins. This won’t affect the current season’s fruit, but if you want to save seed, be careful not to let crops cross-pollinate. Otherwise, the seed won’t be true to type, and the fol lowing season’s crop will potentially be strange-looking or -tasting hybrids.
A week after the last frost date, or when the soil temperature is at least 60°F and the weather has settled, sow six seeds ½ inch deep in a circle on the top of each hill. Thin to the two strongest seedlings per hill.
If planting in rows instead of hills, space vining cultivars 3 to 4 feet apart in rows 8 to 12 feet apart; space bush types 2 to 3 feet apart in rows 4 to 6 feet apart. To conserve space in small gardens, train squash vines on a tripod. Tie three long poles together at one end, stand them upright, and spread them out to form the tripod; plant a squash seed at the base of each pole. You can also grow vining types on fences and well-supported growing nets.
In areas with short growing seasons, sow the seeds indoors a month before the last frost date. Plant two seeds per 3- or 4-inch pot, using potting soil enriched with extra compost. Clip off the weaker seedling after seedlings emerge. Water well just before transplanting, and disturb the roots as little as possible. Full-grown plants can tolerate cold weather, but seedlings are very cold sensitive. Use hot caps or cloches to protect them until the weather turns hot.
Summer squash will produce more heavily than winter squash. In either case, unless you plan to preserve or store a great deal of your crop, two vines of either summer or winter squash are probably adequate to feed four people. Unused seeds are viable for 4 to 5 years as long as you store them properly (as described in the Seed Starting and Seed Saving entry). To spread out the harvest, start a second crop about 6 weeks after the first planting; it will begin to produce fruit about the time your first planting has peaked and the plants are declining.
Growing guidelines: Give seedlings lots of water and keep the planting area moist throughout the growing season. To avoid such diseases as mildew, water the soil, not the foliage, and don’t handle plants when they are wet. Dig weeds by hand until the squash vines begin to lengthen, then spread a thin layer of compost and top it with a thick mulch of hay, straw, or chopped leaves.
About 6 weeks after germination, male blossoms will appear, followed by the first of the female flowers. Squash depend on bees and other insects for pollination; female blooms that drop off without producing fruit probably weren’t fertilized. You can transfer pollen from the male stamen to the female pistil by hand, using a soft paintbrush. Or simply pluck a male flower, remove the petals, and whirl it around inside a female flower.
If your garden soil is less than ideal, side-dress plants with compost or a balanced organic fertilizer or drench them with compost tea when the first fruits set. For instructions on making compost tea, see the Compost entry.
When vines grow to about 5 feet, pinch off the growing tips to encourage fruit-bearing side shoots. By midsummer, winter squash will have set all the fruit they will have time to mature; remove all remaining flowers so the plant can put its energy into ripening the crop. To avoid rot, keep maturing fruit off the soil by setting them on a board or flat rock or by spreading a thick mulch. This is particularly important with winter squash, which take a long time to ripen.
Problems: Well-cultivated squash will be trouble-free as long as you protect young plants with a floating row cover to keep out insect pests. Remove the cover when the plants start to flower to allow for pollination. The two pests most likely to attack are squash vine borers and squash bugs.
Squash vine borers, which are most damaging to winter squash, look like 1-inch-long white caterpillars. They tunnel into stems and can go undetected until a vine wilts. Keep a constant lookout for entry holes at the base of the plants, surrounded by yellow, sawdustlike droppings. Cut a slit along afflicted stems and remove and destroy the larvae inside, or inject the stems with Btk (Bacillus thuringiensis var. kurstaki). Hill up moist soil over the stem wounds to encourage the plant to sprout new roots there.
To prevent borer damage, keep an eye out for the adult borer, a wasplike orange-and-black moth; it lays eggs at the base of the stem in late June or early July in the North, or in April to early summer in the South. During these times, check the base of the stems and just below the surface of the soil regularly for very tiny red-and-orange eggs. Rub the eggs with your finger to destroy them.
Squash bugs are grayish brown bugs up to ¾ inch long; nymphs are similar, but do not have wings. Feeding by adults and nymphs causes leaves to wilt and blacken. Handpick them and drop them in a container of soapy water. Also destroy their red-brown egg clusters on the undersides of leaves. To trap adults, lay boards on the soil at night; the squash bugs will tend to congregate beneath them, and you can destroy the pests the next morning. Planting radishes, nasturtiums, or marigolds among your squash plants may help repel squash bugs. If plants are heavily infested with young squash bugs, try spraying insecticidal soap or neem as a last resort to save your crop.
Striped and spotted cucumber beetles may also attack squash plants. These 1-inch-long black-headed beetles with green or yellow wings can transmit bacterial wilt as they feed. Since these are spring pests, you can avoid them by planting squash later in the season, when cucumber beetles are less prevalent. Handpick daily first thing in the morning when the beetles are sluggish. To make the vines less appealing to the beetles, spray them with kaolin clay as often as twice a week.
In most cases, you can avoid squash diseases by choosing resistant cultivars, rotating crops, and choosing planting sites with good air circulation. Here are some diseases to watch for.
Anthracnose, a soilborne fungus, causes leaves to develop hollow, water-soaked spots that eventually grow large and brown.
Bacterial wilt is a disease that causes plants to wilt suddenly; infected plants usually die quickly.
Downy mildew produces yellow-brown spots on leaf surfaces and downy purple spots on the undersides. These spots eventually spread, and the leaves die.
Mosaic, a viral disease that results in rough, mottled leaves, stunted growth, and whitish fruit, is spread by cucumber beetles and aphids. Reduce the chance of disease by controlling problem insects. (For aphid control measures, see The Top 10 Garden Insect Pests.)
Powdery mildew causes fuzzy white spots on leaves. Affected leaves are distorted, and the plant may appear stunted.
Immediately remove and destroy vines afflicted with any of these diseases, or place them in sealed containers and dispose of them with household trash.
Harvesting: Pick zucchini and crookneck cultivars at a tender 6 to 8 inches long; round types are best when they’re 4 to 8 inches in diameter. Summer squash will continue setting buds until the first frost, but only if you pick the fruit before it matures—that is, just as its blossom drops off the tip. If you allow even one fruit to mature, the plant’s overall productivity may decline. Enjoy summer squash fresh, or preserve them by canning or freezing; they can also be dried, pickled, or turned into relish.
Winter squash will taste bland and watery and won’t store well unless you allow them to fully ripen on the vine. Wait until the plants die back and the shells are hard. A light frost can improve the flavor by changing some of their starch to sugar, but it will also shorten their storage life. It’s better to pick all ripe fruits before an expected frost and cover any unripe ones with a heavy mulch. You can even carefully gather the vines and fruit close together and protect them with tarps or blankets.
Harvest during dry weather. Use a sharp knife or pruners to cut the fruit from the vine, leaving 2 to 3 inches of stem on the fruit. Pulling the fruit off may damage the stem, and the whole fruit may soon rot from that damaged end. (For that same reason, never carry squash by their stems. If a stem breaks off accidentally, use that fruit as soon as possible.) Clean your harvesting knife between cuts to avoid spreading diseases. Handle squash carefully because bruised fruit won’t keep.
Never wash any winter squash that you intend to store. Dry all types in the sununtil the stems shrivel and turn gray; the exception is acorn squash, which doesn’t need curing. If placed in a cool, dry area with temperatures of 45° to 50°F and with 65 to 70 percent humidity, winter squash will keep for up to 5 months. Acorn squash needs a slightly cooler and moister storage area.
Hand-pollinating squash. Male squash blossoms appear first, followed about a week later by female flowers, which have a large swelling (the ovary) just beneath the blossom and a pistil at the flower’s center. Strip petals off a male blossom to expose the stamen; rub the stamen on a pistil to transfer pollen and pollinate the female flower.
Staking plants in the flower and vegetable garden is a task that busy gardeners sometimes skip. In most cases, however, the time you spend staking will be amply rewarded by the improved health and appearance of your garden.
Vining plants virtually require stakes or other support. Top-heavy, single-stemmed flowers like delphiniums, lilies, and dahlias benefit from support. Left unstaked, they are apt to bend unattractively and may snap off during heavy storms. Staking also improves the appearance of plants with thin floppy stems that flatten easily.
Choose stakes and supports that match the needs of the plant and of you as a gardener. They must be tall enough and strong enough to support the entire mature plant when wet or windblown, and they must be firmly inserted in the soil. A stake that breaks or tips over can cause more damage than using none at all. Take care not to damage roots when inserting a stake, and avoid tying the shoots too tightly to the stake. Install the supports as early in the growing season as possible so that the plants can be trained to them as they grow, not forced to fit them later on. When growing plants from seed, install the support before planting.
In the flower garden, choose supports that are as inconspicuous as possible. Thin, slightly flexible stakes that bend with the plant are less conspicuous and may be better than heavier, rigid ones. In general, select stakes that stand about three-quarters of the height of the mature plant. Insert them close to or among the stems so that as the plant grows, the foliage will hide the supports. Choose colors and materials that blend with the plants. Bamboo stakes tinted green are available in a variety of sizes and are a reliable, inexpensive choice for many plants. You can also buy wood, metal, and plastic stakes and trellises and a wide assortment of metal rings and support systems. Soft string, strips of T-shirts, or panty hose work well as ties, and green-tinted twine or plastic-covered wire are inconspicuous ways to fasten plants to their supports.
In the vegetable garden, sturdiness is more important than appearance. Staking vegetables like tomatoes, peppers, and beans makes them easier to cultivate and harvest. It increases yields by preventing contamination with soilborne diseases and allowing for more plants in a given area. Choose tall, sturdy stakes or cages that can support the plant even when it is heavy with fruit, and insert stakes firmly into the ground. Use narrow strips torn from rags or bands cut from stockings to gently fasten plants to supports. See individual entries for more detailed information on staking specific vegetable crops.
Perennial vines such as roses and grapes are commonly grown on trellises or on wires between sturdy posts. For more information on trellises, see the Trellising entry. Raspberries and other brambles are also trellised; see the Brambles entry for support ideas.
Trees and tall shrubs are sometimes staked temporarily at planting to help hold them upright until their roots become established. Fruit trees on dwarfing rootstocks may need to be permanently staked. For more information on staking trees, see the Trees entry.
Individual plant stakes. Sink stakes firmly in the soil at planting time to avoid damage to plant roots or bulbs. Add ties in a loose figure eight as the plant grows.
Pea brush. The traditional staking technique for pea vines, pea brush (also called pea sticks) also works well for annuals and perennials such as coreopsis and baby’s breath. Cut lengths of twiggy brush or branches to the final height of the plants, and push them 6 inches into the ground between the young plants.
Retaining walls, walkways, stepping-stone paths, and terraces are just some of the features you can add to your landscape with stone. Stonework features can fit into any type of landscape and can be formal or informal in design. While designing and building stone features properly is expensive and hard work, once installed, stonescaping is very low maintenance.
Choose a type of stone and a design that fits the style of your garden. For formal gardens, plan on using pavers and stone cut into regular shapes, which conform to the geometric shapes used in this style of landscape. Informal designs can use cut pavers and stone, but they also can incorporate irregularly shaped pavers and stone to create features that are more free-form.
There are many ways to incorporate stone features in your garden. Books on stonescaping are a great place to look for more ideas about what types of stone features would enhance your landscape and how to construct them. See Recommended Reading for some titles. Consider some of the following options.
Stone patios and terraces: These can be built of flagstone cut into squares or rectangles, or from random-shaped pavers. Flagstones may be made of slate, limestone, bluestone, or other types of rock, and the most economical material varies by region. Brick or precast cement pavers are other options for creating flat surfaces in the garden, as are precast landscape pavers, which come in many different colors and styles. Tile and terra-cotta pavers are suitable for gardens in frost-free areas. If your site is under trees, consider a ground-level deck instead of a stone patio or terrace, since a deck can be designed and built to minimize damage to tree roots, and since it’s raised, it can’t be heaved up by root growth.
Patios and terraces can be dry-laid, without mortar between the pavers, or the pavers can be mortared in place. Another option is to install a gravel patio surrounded by a stonework edging to keep the gravel in place.
Walls, walkways, and steps: There are nearly as many ways to plan and construct these elements as there are gardens. All can be dry-laid or mortared, and they can be designed for a formal garden or an informal one. For a steep slope, a low wall, or a series of low walls, is the best option for creating level gardening space. (Stick to walls 3 feet tall or less if you’re planning on building garden walls yourself. Otherwise, consult an expert.) Freestanding walls can be used to separate different parts of the landscape—a formal terrace and a less formal lawn area, for example. Build walls from naturally shaped fieldstone, cut stone, brick, or blocks pre-cast for building. Raised beds with stone walls are another handsome option.
Hardscape walkways and steps are constructed from the same materials as patios and terraces. Keep in mind that materials can be combined to add interest and appeal to walkways and other structures. Edge a pathway with different-size pavers, for example, or work a pattern into a design by combining large flagstones with a network of smaller ones. It’s also a good idea to use a contrasting size or color of paver to mark the edge of a step.
Rock gardens: It comes as no surprise that rocks are essential to a garden designed to grow alpines and other rock-garden plants. Rock gardens can make use of existing rock outcrops on a site, or they can be built over rocks arranged to re-create a natural-looking outcrop. A sloping site is the best choice for a rock garden. Start with a 6-inch layer of coarse gravel, rocks, or broken bricks to provide excellent drainage, then top it with landscape fabric and a 1-foot-deep layer of topsoil. (The landscape fabric keeps the soil from washing down into the drainage layer.) Then arrange the rocks on top of the topsoil. Be sure to position them securely (wedge small stones under large ones to keep them in position) and fill in around them with topsoil. See the Rock Gardens entry for more information on planting and care.
Edgings and ornaments: You can use stone-scaping to create permanent edgings for beds and borders that keep lawn and flowers apart without the need to trim. Stone can be used to create a base for garden sculpture, too, and stones can be used as garden ornaments in their own right. Finally, use stonescaping to surround a water garden and hide the edge of the liner.
Stonescaping is hard work. Before you start a project, make sure that you are physically able to move and place stone or that you can bring in equipment to help you. (A backhoe is invaluable for digging foundations, and a small front-end loader equally so for moving stone, gravel, and other materials, provided your site will accommodate them.) Don’t hesitate to seek professional help, both for design and for construction.
Whether you are building a wall or creating a patio, it’s important to realize that water in the soil is the biggest enemy of any stone feature, especially in northern zones where it freezes, because freezing and thawing cycles will crack stone. If you are building a retaining wall, it’s important to incorporate drainage so that water in the soil behind the wall can drain away. This isn’t a problem for a dry-laid wall, since water can flow through it. In this case, plan on two courses of stone below the soil line and pile the wall so the front edge leans slightly (1 or 2 inches per foot of height) back into the slope of the hill to make the wall more stable. You can build a dry-laid wall right on packed ground or on 6 inches of packed sand. For a mortared wall, use a poured concrete foundation that is below the frost line. You’ll also need drain tile behind the wall along with ditches and/or gutters as well as weep holes through the wall to direct water away from it. Consult your local extension office or building code office for requirements in your area.
Water in the soil is a problem with patios and walkways, since cycles of freezing and thawing will heave them up to create an uneven surface. Set dry-laid paving stones on top of packed sand—use 2 inches in mild climates, 6 inches in very cold regions. Sweep sand over the top of the terrace once the stones are in place to fill the cracks. If you are planning a mortared patio or walkway, you’ll need a poured concrete foundation. Again, consult your local extension office or building code office for requirements in your area.
For steps and walkways, width is another consideration. If you are building a path to the front door or a major walkway into the garden, keep in mind that a width of 5 or 6 feet is necessary for two people to walk side by side. For single-file paths, such as those that may wind through your garden, 4 feet is fine, and for little-used areas, paths as narrow as 2 feet can be perfectly serviceable. If you are building steps, keep in mind that the width of the tread should not be less than 12 inches, and riser height should not be more than 6 inches.
Fragaria × ananassa, F. vesca
Rosaceae
Strawberries are justly celebrated each spring in festivals from coast to coast. Fresh strawberry shortcake, strawberry ice cream, strawberry pie, and chocolate-covered strawberries—or plain berries right from the bush—are hard to beat. The plants are inexpensive, bear a full crop within a year of planting, and are relatively simple to grow.
Garden strawberry cultivars (Fragaria × ananassa) are divided into three types: June-bearers, ever-bearers, and day-neutrals, which flower at different times in response to day length.
June-bearers: These bear fruit in June or July, or as early as April in Florida and California. They produce a single large crop over 3 to 4 weeks. If you want to freeze lots of fruit at one time, plant June-bearers. There are early-, mid-, and late-season cultivars. June-bearers produce many runners and spread rapidly.
Everbearers: These produce a moderate crop in June, scattered berries in summer, and a small crop in late August. They are especially productive in northern areas with long summer days. The total harvest for everbearers, though, is generally less than the total harvest for June-bearers. Plant everbearers if you want berries for fresh eating all season. They produce fewer runners than June-bearers and so are easier to control.
Day-neutrals: These are unaffected by day length. They are extremely productive and bear fruit from June through frost in northern areas, or January through August in milder climates. Unfortunately, day-neutrals can be sensitive to heat, drought, and weed competition. If you are willing to give them the care they need, they’ll reward you with a generous supply of berries throughout the season from relatively few plants. They produce few runners, so they rarely get out of control.
Alpine strawberries: Alpine strawberries (F. vesca) produce small, aromatic berries from early summer through frost. Alpines are grown from seed or divisions and produce no runners. They are carefree and make good ornamental edgings and container plantings.
Whichever type of strawberries you decide to grow, choose disease-resistant cultivars adapted to your climate and daylength; check with suppliers or your local extension office for recommendations. Certified virus-indexed plants are worth the extra cost because the plants are more vigorous and productive.
Strawberries do best in full sun, sandy loam, and a pH of 6.0 to 6.5, although they’ll tolerate less than ideal conditions, provided they have good drainage. Prepare a planting bed by tilling in 3 to 4 inches of compost.
Plant strawberries in spring, as soon as the ground has warmed. In the South, you can plant them in fall as well.
If you buy plants, or receive them through the mail, and can’t plant them immediately, you can store them in the refrigerator for a few days. Be sure the packing material is moist but not soggy. When planting, place the plants in a bucket of water and carry it to the garden with you. This lets plants rehydrate and keeps them from drying out while you’re planting.
Dig a hole deep enough so the roots will not be bent, and make a cone-shaped pile of soil in the bottom. Arrange the roots over the soil cone and gently fill the hole with loose soil. Hold the crown while you work to make sure it remains level with the soil line. Double-check to make sure the crown is neither protruding above the soil nor buried too deeply, and firm the soil with your hand. The following illustration shows you how.
Proper planting level. Set the middle of a strawberry plant’s crown level with the soil surface, and spread out the roots before refilling the planting hole and firming the plant in place.
Most strawberries spread by producing runners—long, slender shoots with a cluster of leaves at the top. The tips root when they touch the ground, forming daughter plants. Each daughter plant sends out its own runners, often in the same season it was formed.
There are three traditional methods for managing strawberries: matted rows, hills, and spaced runners. The methods differ in how runners are managed and how the plants are renewed.
Matted row system: Space plants 1½ to 2 feet apart in rows, with 4 feet between rows. Allow the runners to grow in all directions, so the daughter plants fill in between the mother plants to form a wide, solid row. Remove all flowers that appear in the first 3 to 4 months after planting to give the plants a good start.
The second and subsequent years, rejuvenate the bed immediately after the harvest is finished. Set your lawn mower blade at 2½ inches, mow the entire bed, and rake up all the debris. Then till or turn under the edges of the rows to leave a 1-foot strip down the center with the original mother plants in it. Spread several inches of compost over the bed and work it in on either side of the remaining plants. Water the bed well and renew the mulch between the rows. The undamaged crowns of the strawberry plants will vigorously send out runners throughout the rest of the summer and produce a great crop the following year.
In most cases, even strawberries given the best of care will decline and produce low yields after as few as three seasons. It pays to start a fresh patch in a new location with new plants every few years, so as one declines, the next one is ready to produce.
The matted row system is well suited to June-bearers. For everbearers and day-neutrals, reduce the initial spacing within the row.
Hill system: Space plants 1 foot apart in rows, with 2 to 3 feet between rows. Remove all flowers the first 3 to 4 months after planting to give the plants a good start. Ruthlessly remove every runner so each plant remains a separate hill, channeling all of its energy into producing fruit. You’ll get luscious, large berries and fewer disease problems because the crop will get good air circulation.
Renew the bed the third year by allowing enough runners to root in the row to replace the mother plants, which will be less productive because they have formed multiple crowns. Remove the mother plants in the fall after harvest.
The hill system is well suited to everbearers, since they produce fewer runners than June-bearers. It’s a lot of work to keep up with runner removal with June-bearers.
Modified hill system for day-neutrals: Space plants 7 inches apart each way in double, staggered rows. Allow 3½- to 4-foot aisles between rows. Remove all flowers for the first 6 weeks after planting and all runners during the first growing season. Side-dress with compost or well-rotted manure once a month during the growing season. Mulch around plants to conserve moisture and smother weeds. Renew as for the hill system.
Spaced runner system: The spaced runner system is intermediate between the matted row and the hill systems. Space plants as for the matted row, and allow only a few runners to remain. Pin down the tips so the new plants will be spaced about 8 inches apart each way. Renew and care for as for matted row.
An interesting variation of renewing matted or spaced runners is to preserve a 1-foot strip of plants next to, but not including, the mother plants each year. This may add a few years to the productivity of your patch.
Vigilant weed control is essential to prevent aggressive perennial weeds from outcompeting shallow-rooted strawberry plants. It helps to lay down a thick mulch of straw around the plants during summer.
Strawberries need 1 inch of water per week throughout the growing season. Drip irrigation works best; for information on installing a drip irrigation system, see the Drip Irrigation entry.
After the ground has frozen, cover the plants with fresh straw, pine boughs, or row cover to protect them from alternate freezing and thawing, which can heave plants from the soil. (In climates where a snow cover remains through the winter, strawberries need no special winter mulch.) Pull the mulch away from the plants in early spring so the ground can warm up. Reapply fresh mulch around the plants to smother early weeds. Leave row covers on over winter and into spring for slightly earlier harvests. Remove it when flowers open so bees can pollinate the blossoms.
Spring-planted June-bearers won’t provide a harvest until a year after planting. Everbearers will produce a sizable late-summer crop, and day-neutrals will produce from midsummer through fall the year they’re planted. Fall-planted berries will bear a full harvest the next growing season.
Harvest berries by pinching through the stem rather than pulling on the berry. Pick ripe berries every other day; always remove all ripe berries and any infected or malformed ones from the patch to prevent disease problems. During wet or humid weather, pick out diseased berries every day. Cull the moldy berries, wash your hands, and then pick the ripe berries. At the least, carry a second basket or a plastic bag to put moldy or damaged berries in while you pick.
Verticillium wilt and red stele infect the roots. They are often carried in on new plants and made worse by heavy, wet soil. Remove and destroy infected plants. Replace new plants in a new location or choose resistant cultivars. Vegetables like tomatoes and potatoes are also infected by verticillium wilt, so grow only resistant cultivars where these vegetables have grown in the last 3 years, and vice versa.
Gray mold rots the berries. Wet, humid weather and overcrowded beds with poor air circulation invite it. Keep rows narrow, thin out crowded plants, and remove moldy berries from the plants immediately to control gray mold.
Berries injured by the tarnished plant bug don’t grow or ripen properly but remain small and woody or form hard, seedy tips. See The Top 10 Garden Insect Pests for controls. Birds love strawberries; cover plants with netting, and see the Animal Pests entry for other suggestions. Slugs can take a bite out of your ripe berries; the Slugs and Snails entry lists controls.
Helianthus tuberosus
Asteraceae
This hardy perennial, also called Jerusalem artichoke and sunroot, is a type of sunflower grown for its vitamin- and mineral-rich roots. Cook them as you would potatoes, or enjoy their sweet nutty flavor by adding raw slices to a salad or a stir-fry.
Planting: Plant whole tubers or large pieces in spring or fall in loose, fertile soil. Allow them plenty of room because the root systems can spread widely. If you have the space, plant this crop in an out-of-the-way place, separate from your regular vegetable garden. Place the tubers 1 foot apart in 4-inch-deep furrows spaced 3 feet apart. The plants will grow into 6- to 10-foot single stalks topped with 3-inch, rough-looking sunflowers.
Growing guidelines: Apply a layer of mulch in late spring to keep weeds down and retain soil moisture. This crop spreads rapidly if not controlled. Each year, dig up all the tubers beginning in late summer and continuing until the soil freezes. Chances are you’ll miss a few, which will resprout the following spring to provide next year’s crop.
Problems: Sunchokes are usually free of insect and disease problems. The only problem you may have with this crop is keeping it under control. The invasive root and topgrowth can overwhelm neighboring crops.
Harvesting: Once the foliage has died down (after the first frost), dig roots with a spading fork as needed. The tubers are thin skinned, so keep them moist until you’re ready to eat them, otherwise they will shrivel. Roots keep best in the ground, even over winter.
Helianthus annuus
Asteraceae
While often admired as ornamentals, sunflowers have an amazing variety of uses. They make a good fodder for poultry and livestock, dyes come from the petals, and paper can be made from the stalk pith. Its seeds and seed meal feed countless people, animals, and birds; sunflower-seed oil is used in cooking and in soaps and cosmetics. In the garden, you can grow sunflowers as windbreaks, privacy screens, or living supports for pole beans. Of course, they’re also the stars of any bird garden.
Sunflowers come in a wide assortment of sizes and colors. Some cultivars grow as tall as 15 feet, and the flower heads can be as big as 1 foot across; dwarf types, however, are only 1½ to 2 feet tall. There are also early, medium-height sunflowers that stand 5 to 6 feet tall but have heads that are 8 to 10 inches across. Some cultivars produce a single large flower; others form several heads. A renaissance in sunflower breeding has produced a host of ornamental cultivars for bouquets, including smaller flowers in shades of cream, yellow, mahogany, burgundy, cinnamon, lemon, and bronze, often with bicolored petals and contrasting dark centers. If you’re planning to grow sunflowers for seed, good choices are ‘Snack Seed’, ‘Sunzilla’, ‘Kong’, ‘American Giants’, and ‘Titan’. There are many others. If you fall in love with sunflowers, be sure to visit the Web site of the National Sunflower Association; see Resources.
Planting: If possible, choose a site in full sun on the north side of the garden, so the tall sunflower plants won’t shade your other vegetables. Sunflowers aren’t fussy about soil.
Seedlings are cold resistant, so short-season growers may want to get a head start by planting several weeks before the last frost. In most areas, though, it’s best to wait until the soil is warmer, around the last frost date. Sow seeds 1 inch deep and 6 inches apart. Thin large types to 1½ feet apart and dwarf or medium-size cultivars to 1 foot apart. Water well after planting.
Growing guidelines: Apply a 3- to 4-inch layer of mulch to conserve moisture and keep down weeds. Sunflowers are drought resistant, but they’ll grow better if you water regularly from the time the flowers begin to develop until they’re mature.
Problems: Sunflowers are remarkably trouble-free, but for details on controlling aphids, see The Top 10 Garden Insect Pests. Rotate the crop if leaf mottle, a soil fungus that produces dead areas along leaf veins, becomes a problem. An early autumn may interfere with pollination and cause the plant to form empty seeds; plant earlier the next year. To protect seeds from birds, cover the flowers with mesh bags, cheesecloth, old panty hose, or perforated plastic bags.
Harvesting: Harvest as soon as seeds start to turn brown or the backs of the seed heads turn yellow. The heads usually droop at this time. Cut them along with 2 feet of stem and hang upside down in a dry, well-ventilated place, such as a garage or attic, until fully dry. Rub two seed heads together to extract the seeds, or use a wire brush or similar tool. Spread out damp seeds on a rack until fully dry; store in plastic bags for birds and animal food. To eat, soak overnight in water (or in strong salt water, if a salty flavor is desired), drain, spread on a shallow baking sheet, and roast for 3 hours at 200°F, or until crisp. You can also set out an entire dried head for the wild birds, who prefer black oil sunflower seeds but will eat any, even from dwarf flower heads; or shell the seeds and set them out in a feeder.
See Lathyrus
Ipomoea batatas
Convolvulaceae
Sweet potatoes grow well in a sunny vegetable garden, but you can also grow them in other parts of your home landscape. Try them as a temporary groundcover or a trailing houseplant. In a patio planter, a sweet potato vine will form a beautiful foliage plant that you can harvest roots from in fall.
Sweet potato flesh is classified as moist or dry. Moist, deep orange types are sometimes called yams; the most popular varieties for home gardens are moist types, including ‘Centennial’ and ‘Georgia Jet’. Sweet potatoes are grown worldwide, from tropical regions to temperate climates. This warm-weather crop is remarkably nutritious and versatile. Each fleshy root is rich in vitamins A and C, along with many important minerals. Use them raw, boiled, or baked, in soups, casseroles, desserts, breads, or stir-fries—and don’t forget to try some homemade sweet potato fries!
Planting: Sweet potatoes will grow in poor soil, but roots may be deformed in heavy clay or long and stringy in sandy soil. To create the perfect environment, build long, wide, 10-inch-high ridges spaced 3½ feet apart. (A 10-foot row will produce 8 to 10 pounds of potatoes.) Work in plenty of compost, avoiding nitrogen-rich fertilizers that produce lush vines and stunted tubes. In the North, cover the raised rows with black plastic to keep the soil warm and promote strong growth.
It’s best to plant root sprouts, called slips, which are available from nurseries and mail-order suppliers. Or you can grow your own by saving a few roots from your previous crop or by buying untreated roots (store-bought sweet potatoes often are waxed to prevent sprouting). About 6 weeks before it’s time to plant sweet potatoes outdoors in your area, place the roots in a box of moist sand, sawdust, or chopped leaves in a warm spot (75° to 80°F). Shoots will sprout, and when they reach 6 to 9 inches long, cut them off the root. Remove and dispose of the bottom inch from each slip, as that portion sometimes harbors disease organisms.
Sweet potatoes mature in 90 to 170 days and are extremely frost sensitive. Plant in full sun 3 to 4 weeks after the last frost when the soil has warmed. Make holes 6 inches deep and 12 inches apart. Bury slips up to the top leaves, press the soil down gently but firmly, and water well.
Growing guidelines: If you’re not using black plastic, mulch the vines 2 weeks after planting to smother weeds, conserve moisture, and keep the soil loose for root development. Occasionally lift longer vines to keep them from rooting at the joints, or they will put their energy into forming many undersized tubers at each rooted area rather than ripening the main crop at the base of the plant. Otherwise, handle plants as little as possible to prevent wounds that might be invaded by disease spores.
If the weather is dry, provide 1 inch of water a week until 2 weeks before harvesting, then let the soil dry out a bit. Don’t overwater, or the plants—which can withstand dry spells better than rainy ones—may rot.
Problems: Southern gardeners are more likely to encounter pest problems than gardeners in northern areas.
Sweet potato weevils—¼-inch-long insects with dark blue heads and wings and red-orange bodies—puncture stems and tubers to lay their eggs. Developing larvae tunnel and feed on the fleshy roots, while adults generally attack vines and leaves. They also spread foot rot, which creates enlarging brown to black areas on stems near the soil and at stem ends. Since weevils multiply quickly and are hard to eliminate, use certified disease-resistant slips and practice a 4-year crop rotation. Destroy infected plants and their roots, or place in sealed containers and dispose of them with household trash.
Fungal diseases include black rot, which results in circular, dark depressions on tubers. Discard infected potatoes, and cure the undamaged roots from the same crop carefully. Don’t confuse this disease with less-serious scurf, which creates small, round, dark spots on tuber surfaces but doesn’t affect eating quality. Stem rot, or wilt, is a fungus that enters plants injured by insects, careless cultivation, or wind. Even if this disease doesn’t kill the plants, the harvest will be poor. Minimize the chances of disease by planting only healthy slips; avoid black and stem rot by planting resistant cultivars. Reduce the incidence of dry rot, which mummifies stored potatoes, by keeping the fleshy roots at 55° to 60°F.
Harvesting: You can harvest as soon as leaves start to yellow, but the longer a crop is left in the ground, the higher the yield and vitamin content. Once frost blackens the vines, however, tubers can quickly rot.
Use a spading fork to dig tubers on a sunny day when the soil is dry. Remember that tubers can grow a foot or more from the plant, and that any nicks on their tender skins will encourage spoilage. Dry tubers in the sun for several hours, then move them to a well-ventilated spot and keep at 85° to 90°F for 10 to 15 days. After they are cured, store at around 55°F, with a humidity of 75 to 80 percent. Properly cured and stored sweet potatoes will keep for several months.
See Aster
Lilac. Deciduous, spring-blooming shrubs or trees.
Description: Syringa laciniata (aka S. × laciniata), cutleaf lilac, has a rounded, arching form and grows to a mature height of about 6 feet. Its leaves are opposite, often deeply lobed. Fragrant, lavender flowers are borne in 3-inch-long, loose clusters along the branches in spring. Cutleaflilac is one of the few lilacs to flower reliably in the South. Zones 4–8.
S. meyeri, Meyer lilac, is a broad shrub, 4 to 8 feet tall. It bears ¾- to 1¾-inch, dark green, oval leaves. Violet-purple, fragrant flowers are borne in 4-inch clusters in spring, covering the plants. Zones 4–7.
S. reticulata, Japanese tree lilac, is a large shrub or small tree with a rounded crown, growing to a mature height of 30 feet. The 5-inch, dark green leaves are broad and nearly heart-shaped. Plants bloom in summer, bearing fragrant yellowish white flowers in loose, lacy, 6- to 12-inch clusters at the branch tips. Zones 3–7.
S. vulgaris, common lilac, is an upright, vase-shaped shrub that can grow to a mature height of 20 feet. Dark green, 2- to 5-inch leaves are basically heart-shaped. The flowers are purplish or white, fragrant, and borne in 4- to 8-inch terminal clusters in spring. Zones 3–7.
How to grow: Provide lilacs with full sun and good drainage. Once established, they need minimal watering. Remove spent blooms, or flower bud formation for the following year may be inhibited by seed development. Prune immediately after bloom by removing a few of the oldest stems a few inches above ground level each year. This will keep the plant growing vigorously. Powdery mildew can be a problem. Choose cultivars that are resistant to this fungal disease, and don’t plant them in shade. Meyer lilac is mildew resistant.
Landscape uses: Japanese tree lilac makes a fine street tree. The other lilacs are useful as hedges, specimens, or in shrub borders.
