Trilliums are the most familiar and beloved of Michigan’s woodland wildflowers. They thrive in the rich, acidic soil of deciduous woodlands and flower in May before the tree canopy fills out, often forming large colonies that carpet the forest floor. The blooms open slowly and may last into early June before they turn purple and fade.
Trilliums belong to the lily family. They have three-petal flowers above three pointed leaves on a single stem. The above-ground part of the trillium is technically a flowering scape, which means the “stem” isn’t a true stem, but just an extension of the horizontal rhizome, and the “leaves” aren’t true leaves, but rather are bracts. At least 10 species of trillium grow in Michigan. The most common is Trillium grandiflorum, also known as the great white trillium or wood lily. Each trillium flower produces a single seed case. Attached to the seed case are small fleshy structures called elaiosomes, which are rich in lipids and proteins. These elaiosomes attract ants, which take the seed cases to their nests and feed the elaiosomes to their larvae. After the larvae have finished eating the elaiosomes, the ants take the seeds to their waste disposal areas, where the seeds germinate and grow.
Trilliums are beautiful to look at, but also extremely fragile. Picking the flower doesn’t harm the plant but does keep it from making seeds that year. Picking the green bracts can kill the plant because if you remove them, the plant can’t perform photosynthesis and will die. Trilliums grow very slowly; it takes decades to establish a large, healthy colony. When propagated by seed, a root appears after a year underground, followed by a little rhizome. The seedling then remains there for another year before growing its first bract. Two more years will pass before it produces three bracts and several more years before it produces a flower. In an ideal situation, a trillium may be seven or eight years old before it produces its first flower. If conditions aren’t ideal, it can take a decade.
You should know that picking certain species of trillium is illegal in Michigan. Under the Michigan Endangered Species Act 203 of 1974, the toadshade, prairie trillium, and snow trillium are listed as threatened and painted trillium is listed as endangered. Picking any of them on public land is a misdemeanor punishable by fine and imprisonment.
Trilliums are a celebrated rite of spring in Michigan and are most commonly celebrated in northwest Michigan where they carpet beech/maple hardwood forests with abandon. But did you know you can find them in southern Michigan as well? In mature forests in southern Michigan that have been left undisturbed, you can often find them. Trillium required hardwood forests with undisturbed soil. We recently found trilliums in Bay County along a rail trail along the Saginaw Bay. So get out there in the early spring forests and look for the white beauties.