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A rainbow of bulbs to brighten the spring garden

By Joel M. Lerner
Saturday, March 27, 2010; E05

The Washington area is glorious in springtime, not only because of its famous cherry blossoms, but also because of an abundance of flowering bulbs.

Spring steals the show, of course. But daffodils, tulips, fritillarias, hyacinths, trilliums, snowdrops, winter aconites, scillas, crocuses and grape hyacinths are only the beginning of the parade of blooming bulbs. Different varieties flower almost year-round.

The term "bulb" generally refers to a variety of bulbous-rooted plants with specialized thick or fleshy underground plant growth used for storing food. These can be corms, rhizomes, tubers or bulbs.

But botanically, true bulbs consist of a leaf or flower bud encased in food storage layers called scales. Many spring-blooming flowers, including daffodils and tulips, are true bulbs and are planted in the fall.

Spring, not fall, is perfect for planting many summer- and fall-blooming bulbs. Plant them as soon as the chance of frost is past -- May 1 in the Washington region.

Try some Chinese ground orchids, blackberry lilies, canna lilies, elephant ears, lilies of the valley, crocosmias, hardy cyclamens, dahlias, summer hyacinths, gladioluses, day lilies, irises, or true lilies for a coordination of flowers through summer into fall.

Here are some bulbs, corms, rhizomes and tubers to plant this spring:

Chinese ground orchid (Bletilla striata): Early spring is the time to plant this "terrestrial" (grown in the ground) orchid. By late spring, lavender or white flowers open on two-foot-tall scapes and bloom for about two weeks. In fall, mulch with a few inches of compost for winter protection. Install in a moist, well-drained area with full eastern sun and hot afternoon shade using lots of organic material. Grow in an undisturbed area to form a colony.

Blackberry lily (Belamcanda chinensis): Drought- and heat-tolerant with few pests, this Asian member of the iris family should be planted in spring just below the soil's surface. The rhizomatous root will develop strap-shaped, iris-like leaves, blooming in summer on two- to three-foot tall stems with yellow, orange and purple flowers. Suitable for any type of soil, they should be kept moist during the growing season.

Canna lily: Cannas are available in a range of hybrids, with blooms whose colors include rose, pink, yellow, red and orange. They can grow three to six feet tall. Their greatest asset is that they bloom all summer if they are deadheaded. Plant about one inch deep in well-drained soil rich in organic material. They grow best in protected sites with full sun. In fall, lay a few inches of mulch over the roots for winter protection or dig them up and store them in a cool, dry place.

Elephant ear (Calocasia esculenta): Grown ornamentally for its huge leaves, this tuber is used to make poi, a popular food in the plant's native East Indies and tropical Asia. It loves water and will grow in continually wet sites that are well drained and high in organic content in sun or shade. Plant them three feet apart and keep them moist. Often planted as an annual, tubers can be dug in fall and replanted in the spring.

Lily of the valley (Convallaria majalis): Lily of the valley will colonize into a spring-flowering, low-growing ground cover. This member of the lily family loves cold and needs partial shade to thrive. Warmth will make the rhizome sprout, so plant them as soon as possible. Install one inch deep in rich soil. Then, do not disturb. Note that all parts of this plant are poisonous. This exceptionally fragrant flowering plant should be planted out of children's reach.

Crocosmia: Hybrids are available with orange, red or yellow flowers. This South African member of the iris family is a summertime standout, grown in full sun in well-drained, sandy loam. It should be planted three inches apart in two inches of soil. This hardy corm flowers on two- to four-foot-tall stems and has sword-shaped foliage. Mulch in the fall for winter protection.

Hardy cyclamen (C. hederifolium): Cyclamen are hardy shade plants, making them good bloomers for most gardens. They produce pink or white flowers in late summer and early fall. Corms create flowers from small, twiggy protuberances. Plant them with the flat sides down, no deeper than two inches, because roots and leaves both emerge from top.

Dahlia: This native of Mexico and Central and South America is a tuberous root plant that has been hybridized for the varieties of flowers it produces. Blossoms are bred for size, flower, form and color. Bicolor varieties are magnificent. There are 12 groups offering a grand choice of colors and flower types. Plant tubers one to three inches deep in rich, sandy loam for flowers from summer into fall. Many garden varieties will winter over with some mulch protection.

Summer hyacinth (Galtonia candicans): This South African native produces white flowers for several weeks in summer on four-foot-tall stalks. Requires good soil preparation with excellent drainage and light soil rich in compost and sand. Plant this true bulb six inches deep in full sun, spacing bulbs about one foot apart. The bulbs fare best left in ground and mulched for the winter.

Gladiolus: This predominantly South African iris-family corm is available in every color but blue and is known for late-spring and early-summer flowers. It requires full sun and light, moist, well-drained soil. Plant corms about six inches apart and six inches deep. Insecticide and fungicide are needed to ensure protection of corms. Hardier varieties, like hybrids of Turkish gladiolus (G. communis subsp. byzantinus), should be left in the ground and mulched for winter protection. They will return for several years. If dug and stored over winter, corms must have good air circulation.

Day lily (Hemerocallis): The day lily hails from Japan and Europe. It is a popular and dependable spring and summer flowering plant with tuberous roots, hybridized to yield many colors and forms. They are easily divided. Plant them in full sun, just below the soil surface, about two feet apart.

Iris. There are many irises native to different parts of the world. The most popular have rhizomatous roots and bloom in late spring and summer. Bearded iris is an eye catcher in late spring. Japanese irises have large, almost flat flowers that can be up to 10 inches wide, blooming later in the season. They like boggy conditions while growing, but will tolerate dryness after pushing new growth. Both have hybrids available in white, blue, lavender, pink and yellow.

Lilium. These are fragrant and colorful "true" lilies (Lilium species), true bulbs that grow one to seven feet, depending on the species and hybrid. There are at least nine divisions, based on the country of origin. All prefer moist, well-drained soil that's high in organic material. Planting depths vary with bulb size.

Designs with bulbs are most effective when installed in drifts or waves of the same color. Always buy multiples of eight to 10 or more of each variety. If you like to mix colors that bloom at the same time, sprinkle them evenly for the best effect.

Specialized bulb-planting tools push down into the soil and remove plugs at the proper depth. There are also augers that fit on a half-inch electric drill and are sold at garden or home centers. Hold the drill with both hands, wear goggles and allow the auger to do the work. If the auger hooks a root, reverse the drill's rotation.

You can buy or order bulbs at garden centers. A couple of mail order sources are Brent and Becky's Bulbs, 877-661-2852, http://Brentandbeckysbulbs.com, or Dutch Gardens, 877-527-7575, http://Dutchgardens.com.

Joel M. Lerner is president of Environmental Design in Capitol View Park.

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