The Trillium genus belongs in the lily plant family (Liliaceae) and contains numerous perennials native to the United States. Most trillium species bloom during the spring and early summer. If you would like to grow trillium flowers, select a variety according to your hardiness zone, the plant's mature size, flower color and intended use.
Green trillium (Trillium viride) performs well in hardiness zones 5 to 8. This trillium species reaches up to 18 inches in height and spread. Green or yellow-green flowers appear in April and May. Also called the wood trillium, this plant features leafless stems and deep green leaves. The foliage generally dies by the middle of summer. Green trilliums like humus, well-drained soils in partial to full shade positions. Gardeners often use the green trillium in wildflower gardens.
The red trillium (Trillium erectum), sometimes called the stinking-Benjamin, features diamond-shaped green leaves and stems that range from 6 to 18 inches tall. Solitary, deep red flowers with backward curving petals bloom from April through June. These foul-smelling flowers wither in two or three weeks, giving way to red fruits that attract birds. This perennial typically performs well in hardiness zones 4 to 8. This plant prefers acidic, humus soils in partial shade to full sun locations. Red trillium plants perform well in rich, moist woodland areas.
The pacific trillium (Trillium ovatum ) ranges from 8 to 20 inches in height. This perennial features broad green leaves and long, naked stalks. Flowers display from February through June, featuring white blossoms that fade to pink within a week. This trillium variety also is called the western wakerobin because the flowers bloom around the time that robins appear in the spring. This trillium species prefers cool soils in shady sites. Pacific trillium plants work well planted along streams and moist slopes in hardiness zones 5 to 8.
Nodding trillium plants (Trillium cernuum), also called whip-poor-will flowers, bear large green leaves and arching stems that reach up to 18 inches tall. Nodding, white flowers with pink anthers bloom in May, followed by purple berries that ripen to red. These inedible berries contain toxic principles. Winter hardy in zones 2 to 9, this type of trillium requires moldy, rich soils in shady positions. Gardeners often plant nodding trillium in damp woodland margins.
The painted trillium (Trillium undulatum) features a thin, arching stalk that reaches up to 16 inches long. This trillium species bears large, bluish-green leaves and white flowers with pink or purple markings. These blossoms appear from April through June, followed by red berries in the early autumn. Winter hardy to zone 4, the painted trillium tolerates various lighting conditions but prefers acidic, sandy soils. The painted trillium works well planted in moist woodland areas.
Slender trillium plants (Trillium gracile), sometimes called graceful trilliums, need moist, acidic soils in shady, undisturbed locations. Winter hardy to zone 6, this trillium variety bears mottled, green leaves and flowers that appear in April. The blossoms emerge a maroon color but turn attractive, yellowish-green shades with age. Mature plants range from 8 to 12 inches in height. Gardeners often plant the slender trillium in woodland gardens.