Trillium flowers bloom during the late spring and summer months. These three-petaled flowers come in hues of white, yellow, crimson or purple. Wildflowers native to North America, trillium makes a rewarding shade plant but takes years to establish and thrive. Plant either from seed or from rhizome in the late summer to early fall.
Trilliums prefer a rich, moist soil with lots of organic material. These flowers grow well in shady spots and can grow beneath tree canopies. They do best with a pH near neutral or slightly acidic.
Different types of trillium grow from USDA plant hardiness zones 3 to 8. White trillium (Trillium grandiflorum) grows naturally throughout the northeastern United States and as far south as Georgia, though this flower is endangered in Maine and nearly so in New York. The purple toadshade trillium (Trillium underwoodii) grows in the southeastern United States as far south as Florida.
Planting From Seed
Trillium planted from seed can take up to two years to germinate, according to the Alabama Cooperative Extension Service. Collect seed from trillium flowers in the summer months. Then prepare the ground for planting by digging up the soil in your chosen area, breaking apart soil clumps and removing rocks and other debris from the seed bed. Rake the soil back into an even layer once you've dug up and aerated the soil. Dig furrows 1/4- to 1/2-inch deep. Then sow trillium seeds in the furrow, spacing them 1 to 2 inches apart. Cover over the soil and water the seed bed thoroughly. Continue to water it when the soil becomes dry until the seeds germinate.
Planting From Rhizome
Prepare the soil in the same manner when planting trillium from rhizomes. Then dig one hole for each rhizome that's twice as wide as the rhizome and 2 inches deeper. Space the holes 10 inches apart. Place the rhizome in the hole with the pointy eye facing up. Cover the rhizome with 2 inches of soil. Water the ground until the soil becomes saturated then continue to water during dry periods.
Trillium patches can take up to 17 years to get established but may live up to 70 years, notes Skidmore College. Amending the soil with lots of compost will help new trillium get established. White-tailed deer graze on white trillium flowers, so avoid planting this flower if your area has an invasive deer population.