Bulbs

Darrow M. Watt
Lilium Asiatic Hybrids

• True bulb
• All zones
• Full sun or partial shade
• Regular watering; never let root zone dry out

Asiatic Hybrid lilies bloom in early summer on strong, erect stems 1 1/2 to 4 1/2 feet tall. The 4- to 6-inch blossoms come in colors ranging from white through yellow and orange to pink and red. The Oriental Hybrids bloom later, in midsummer to early fall. Their 2- to 6-foot stems bear big (to 9-inch), fragrant flowers with pink or white petals marked with center stripes and speckles.

Plant bulbs as soon as possible after you get them, since they do not store well. If you must delay, store them in a cool place. Before planting, check bulbs carefully; if they look shriveled, place them in moist sand or peat moss until the scales plump up and roots start to form.

Space bulbs 1 foot apart. Cover smaller bulbs with 2 to 3 inches of soil, medium-size ones with 3 to 4 inches, and larger ones with 4 to 6 inches. Viral (mosaic) infection is an incurable problem; to avoid it, buy healthy bulbs from reliable sources. Destroy any lilies that have mottled leaves or are seriously stunted.

Saxon Holt
Crocus 'Advance'

• Corm
• Zones 1-24, 30-45
• Full sun or partial shade
• Regular watering during growth and bloom

Most crocuses bloom in late winter or early spring, bearing tubular, 1 1/2- to 3-inch-long flowers in a rainbow of colors. Others, including C. sativus (the saffron crocus) and C. speciosus, bloom in fall, with flowers rising from bare earth weeks or even days after planting. Plant corms of both spring- and fall-blooming types as soon as they are available in autumn, setting them 2 to 3 inches deep and 3 to 4 inches apart in light, porous soil.

Jerry Pavia
Narcissus 'Early Splendor'

• True bulb
• Zones 1-24, 28-45, except as noted
• Full sun
• Regular watering during growth and bloom

Easy to grow and generous with their spring flowers, daffodils are classified into 12 divisions, based in part on differences in flower form; among these groups are the familiar trumpet daffodils, large- and small-cupped types, and double daffodils. Besides yellow and white, colors include shades of orange, apricot, pink, and cream.

Most kinds are hardy in the zones listed; exceptions are the fragrant Tazetta Hybrids, hardy just to 10 degrees F/-12 degrees C, and dainty hoop petticoat daffodil, hardy to about -10 degrees F/-23 degrees C.

Plant bulbs twice as deep as they are tall, spacing them about 6 to 8 inches apart.

Charles Mann
Dahlia

• Tuberous root
• All zones
• Full sun, partial shade where summers are hot
• Regular watering during growth and bloom

Blooming from summer through fall, dahlias are available in numerous colors and floral forms. Flower diameter ranges from 2 to 12 inches; plant height varies from about a foot to over 7 feet (stake varieties that grow more than 4 feet tall). Plant after the last frost in spring, setting roots 4 to 6 inches deep. Space tall varieties 4 to 5 feet apart, shorter ones 1 to 1 1/2 feet apart.

Though roots can be left in the ground where winter temperatures remain above 20 degrees F/-7 degrees C, gardeners in most areas prefer to dig them annually. After foliage yellows in fall, cut back stalks to about 4 inches. Dig clumps of roots and let dry in the sun for several hours. Then place in single layers in boxes, cover with dry sand or sawdust, and store in a cool spot over winter. In spring, divide (if needed) and replant.

Susan A. Roth
Hemerocallis

• Tuberous root
• All zones
• Full sun or light shade
• Regular watering during growing season

Tough and trouble free, daylilies are familiar components of perennial borders. Growing in large clumps, the arching, sword-shaped leaves may be evergreen, semievergreen, or deciduous, depending on the type.

Modern hybrids grow 1 to 6 feet tall and bloom in spring and summer, producing flowers that vary from 3 to 8 inches wide and come in a wide range of colors. Each flower lasts just one day (hence the common name), but buds open on successive days to prolong the display.

Set out the tuberous roots in fall or early spring, planting them 1/2 to 1 inch deep and 2 to 2 1/2 feet apart. Set out plants from containers at any time from early spring through midautumn.

Susan A. Roth
Hyacinthus

• True bulb
• All zones
• Full sun
• Regular watering during growth and bloom

Dutch hyacinth is a spring bloomer with foot-tall spikes densely packed with waxy, bell-like, fragrant flowers in shades of blue, purple, red, pink, buff, and white. It grows best in cold-winter areas, where it lasts from year to year; in these zones, plant in September or October. In mild areas, bulbs will not persist and are best treated as annuals; plant from October to December. Set bulbs 4 to 5 inches deep, 4 to 5 inches apart.

Claire Curran
Gladiolus

• Corm
• Zones 4-9, 12-24, 29-33
• Full sun
• Regular watering during growth and bloom

These long-time favorites have sword-shaped leaves and flaring funnel-shaped flowers borne in slender spikes. The large summer-flowering garden kinds (grandiflora hybrids) grow 3 to 6 feet tall and come in a wide variety of colors.

Plant corms in spring after soil has warmed; they'll bloom in 65 to 100 days. If you plant corms at 1- to 2-week intervals over a period of 4 to 6 weeks, you can enjoy an extended flowering season. Set each corm about 4 times deeper than it is thick; space 4 to 6 inches apart.

In the zones listed, corms can overwinter in the ground, though many gardeners prefer to dig them. In colder regions, they must be dug and stored in a frost-free location. Dig after the leaves turn yellow; cut off and discard tops.

Arrange corms in a single layer in a dry, dark area and let dry for 2 to 3 weeks. Pull off and discard old corms and roots. Store new corms over winter in onion sacks or nylon stockings hung in a cool, well-ventilated area.

Saxon Holt
Muscari armeniacum

• True bulb
• Zones 2-24, 29-43
• Full sun or light shade
• Regular watering during growth and bloom

Grape hyacinth's narrow, grassy leaves emerge in fall and live through winter's cold and snow. Small, urn-shaped blue flowers, carried in 8-inch spikes, bloom in spring. Plant bulbs in fall, setting them 2 inches deep and 3 inches apart.

Claire Curran
Iris

• Rhizome
• Zones 1-24, 30-45
• Full sun or light shade
• Regular watering during growing season

The most widely grown irises are the bearded irises that grow from rhizomes (though there are also beardless rhizomatous irises and bulbous irises). Bearded irises come in a dazzling array of colors and color combinations; plant size varies widely as well.

Plant in July or August in cold-winter zones, in September or October where summers are hot. Space rhizomes 1 to 2 feet apart, setting them with their tops just beneath the soil surface and spreading out the roots.

SNOWDROP (Galanthus nivalis)

• True bulb
• Zones 1-9, 14-17, 31-45
• Full sun or partial shade
• Regular watering during growth and bloom

Snowdrops are among the first bulbs to bloom as winter draws to a close. Plants grow 6 to 8 inches tall, bearing one nodding, bell-shaped white flower on each stalk. Best suited to cold-winter climates. Plant bulbs in fall, setting them 3 to 4 inches deep and 3 inches apart.

Norman A. Plate
Tulipa hybrids

• True bulb
• Zones 1-24, 28-45
• Full sun
• Regular watering during growth and bloom

Hybrid tulips come in a multitude of colors, including bright shades, pastels, and even near-black. Flowers very widely in form, too, from the classic egg-shaped blossoms to those that look like lilies or peonies.

Bloom season ranges from mid- to late spring, depending on variety. Most need an extended period of winter chill for best performance, but even in cold-winter areas they may not put on a good show after the first year. To encourage repeat flowering, feed with a nitrogen fertilizer before bloom; be sure to allow foliage to yellow and wither before removing it after bloom. In mild climates, refrigerate tulip bulbs for 6 weeks before planting, and treat the plants as annuals.

Plant bulbs in fall, setting them three times as deep as they are wide; space 4 to 8 inches apart, depending on the ultimate size of the plant.