If you walk a shaded forest trail in May and see a knee-high plant with three large white petals sitting above three green leaves, you have found a Large White Trillium (Trillium grandiflorum). The whole plant is built on the number three, and a single flower can take up to seven years to first bloom from seed.
What it looks like
Mature plants are 30 to 40cm tall. Three broad oval leaves grow in a single whorl at the top of the stem, and from the center of that whorl a single flower stalk rises with three pure white petals and three green sepals. Each petal is 4 to 7cm long with slightly wavy edges. As the flower ages over a week or two, the petals slowly turn from white to pink to deep magenta before they drop.
When and where
- Season: Late April through May for the bloom. Leaves stay through midsummer, then the whole plant dies back to its underground rhizome.
- Habitat: Rich deciduous forest floors with moist well-drained soil, mostly under maple, beech, and basswood canopies.
- Best time: Mid-morning on a clear day when the white petals catch the dappled light from above.
Ants plant the next generation
After the flower fades, trillium seeds form with a fatty outer coating called an elaiosome. Ants find the seeds, drag them back to the colony, eat only the fatty coating, and discard the actual seed in a nutrient-rich underground waste pile. That is where the next trillium sprouts. The whole strategy is called myrmecochory, and it explains why trilliums spread so slowly. They can only move as far as an ant will carry a seed in one trip.
Spot one this weekend
Large white trillium is Uncommon because they need old-growth-style forest soil and seven years to reach flowering size. The best places to find them are mature deciduous forests in the Appalachians, the Great Lakes region, and southern Ontario. Walk slowly along the forest floor away from the trail edge and look for the three-leaf whorl first. The flower above will be obvious. Do not pick one. A picked trillium often kills the whole underground rhizome and erases seven years of growth.