The three waxy white petals alternate with three green sepals to form a flower that is funnel-shaped at the base and open at its apex. The petals generally turn pink with age, but in some populations pink flowers are produced directly from the bud stage. In the large drifts and stands that large-flowered trillium forms, one finds a magnificent mosaic of color. Bees and butterflies reportedly visit the flowers with some regularity. The seeds bear an oil body called an elaiosome that functions as an attractant to ants that disperse the seeds and harvest this body as their food reward.
Many spring ephemerals attract seed-dispersing ants through the production of an elaiosome.
Propagation Large-flowered trillium has long been considered a valuable component of woodland gardens. Planted in a soil rich in leaf mold in a shaded site, this plant can be long-lived. Uneven soil moisture, drought, and inadequate preparation of soils are detrimental to garden plants. The depletion of natural Trillium populations through commercial collection of rhizomes is cause for concern among botanists and horticulturists. Furthermore, plants started from collected rhizomes often have a low survival rate.