Dune thistle is a gorgeous plant, endemic to the shores of Lake Michigan, the southern shores of Lake Huron, and a few locations on the southern shores of Lake Superior. Its colors are muted and subtle; the foliage has a whitish cast, and the flowers are whitish or pale pink, setting it apart from most other thistles in the Midwest.

Unfortunately, dune thistle is a threatened species—meaning it is headed toward endangered species status—as a result of the most dangerous invasive species on our planet: Homo sapiens. Shoreline development, road work, hikers, beach-goers, dune buggies and other off-road vehicles, and (especially) the intentional introduction of a seed-eating weevil (Larinus planus) as a "biological control" against invasive thistles like Cirsium arvense (Canada thistle), are all factors threatening the dune thistle. As a result, the plant is listed as threatened by the federal government, as well as by the states in which it grows.

the nearly whitish foliage and pale flowers make dune thistle easy to recognize

flowers are whitish to pale pink

spines on the flowerheads are fairly short

stems are whitish and finely fuzzy

leaves are pinnate, with linear lobes

undersurfaces of leaves are white and finely fuzzy

a monarch butterfly enjoying dune thistle . . . according to researchers at the Chicago Botanic Garden, dune thistle supports "more pollinators than any other species in the dune community" (2018)

immature, unopened flower

sign in Emmet County, Michigan

mature flower

a first-year seedling (particularly susceptible to human disturbance); plants later develop deep taproots and begin to flower within 2–8 years

References: GN Jones 1971, Havens et al. 2012, Voss & Reznicek 2012, Mohlenbrock 2014, Chicago Botanic Garden 2018, USDA 2018.

Kuo, Michael & Melissa Kuo (July, 2018). Cirsium pitcheri (dune thistle). Retrieved from the midwestnaturalist.com website: www.midwestnaturalist.com/cirsium_pitcheri.html

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