People frequently used the word "lilies" to describe plants that are not lilies at all, according to Associate Professor Cynthia Haynes of Iowa State University's Department of Horticulture. Belonging to the Lilium family, true lilies are bulb plants or hybrid cultivars combining traits from different native plant strains. Some lily varieties tolerate winter temperatures as low as -40 degrees Fahrenheit. These ornamental plants provide garden color and beauty that belies their toughness.
Asiatic Hybrid Lilies
Bred from from Japanese tiger lilies, Chinese nodding and David lilies, and other lilies native to Asia, these easy-to-grow plants are among the earliest blooming lilies. They are available in a broad of colors, including white, yellow, orange, pink, purple and red. Asiatic hybrid lily flowers face upward, outward or downward. They grow nearly anywhere, according to the North American Lily Society, but are especially attractive in sunny spots with other blooming plants. A general lack of fragrance is this lily type's single drawback.
Shade-loving and early blooming lilies, martagons are tall plants that make good additions to the back of woodland garden. They may not bloom heavily in the first year after planting. Once established, however, they produce large numbers of small downward-facing blooms. Flower colors include white, lavender, pink, dark red and pale orange. Many varieties have contrasting speckles, according to the North American Lily Society.
American Hybrid Lilies
Interbreeding lilies native to Western North America has created a distinctive class of hybrid lily bulbs, says the North American Lily Society. Jointed scales form bulbs that produce plants with nodding, downward-facing blooms. The flowers' petals curl up and back to touch in the center, while their showy stamens extend down. In the right conditions--with filtered shade and light, cool soil--they will colonize into extensive clumps.
The Stargazer--popular among florists for its large, delightfully fragrant, white and pink blooms--is among the best known Oriental lilies. Although they are more demanding to grow than Asiatic hybrids, their fragrance alone makes these lilies worth the effort, says the North American Lily Society. Other varieties of Oriental lilies may be white, crimson, pink or salmon. They struggle in hot, humid conditions. Provide a partly shady location and regular water. Rich, acidic (pH below 7.0) soil and a root-cooling mulch will help them flourish.
Among the most eye-catching of all bulb plants, trumpet lilies stand between 4 and 8 feet high. Their outward-facing, large trumpet-like blooms are exceptionally fragrant, says Haynes. Trumpet hybrids are available in white and several unusual colors including apricot, deep golden yellow, and plum. Many varieties have petal surfaces of one color and undersides of another. These tall lilies benefit from wind protection.