Native Plant of the Week: Trillium

Common trillium (Trillium grandiflorum) flower bud.

Each week we showcase a plant that’s native to the continental United States. This week’s plant is trillium.

Think ‘trillium’ and you  might channel the white-blossomed common trillium (Trillium grandiflorum) found throughout Michigan in deciduous forests. Whether you see just one in bloom or a forest floor dappled with T. grandiflorum, your experience will be anything but common.

Of the 43 species of trillium worldwide, 38 can be found in N. America. As many of 10 trillium species have been observed growing in Michigan, including T. cernuum (nodding trillium), T. flexipes (drooping trillium), and T. sessile (toadshade). Three are listed as threatened in Michigan: T. nivale, T. recurvatum, and T. sessile.

Trillium come in many different colors and shapes. Even botanists may struggle to identify one trillium from another since there can be a lot of variation in color forms and different species may hybridize.

Ants harvesting trillium seeds. Photo by Amy Hoffman Mawby.

T. luteum’s inflorescence is yellow (and scented) and its leaves mottled. Its native range is the southeastern United States. T. erectum’s flowers (stinking Benjamin) are red and may exhibit a “wet dog” smell.

In general trilliums prefer part to full shade and appreciate a winter leaf-litter cover. Trillium are long-lived plants that spread very slowly by underground rhizomes or by seed.

Fascinating eco-fact: As much as a third of spring-flowering native plants—trillium being one of them—have evolved a strategy of seed dispersal by ants. The ants are attracted to small structures attached to the seeds called elaiosomes, which consist of lots of nutritious fats that the ants feed to their larvae. The seed itself is then discarded, helping to grow new plants. Pictured: Ants harvesting trillium seeds. Photo by Amy Hoffman Mawby.

As always, please do not collect any plants in the wild, including trillium, especially since some trillium are listed as threatened. Find a reputable nursery and ask how their trillium have been cultivated. Some trillium, such as T. luteum and grandiflora, can be purchased from plant nurseries.

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