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Species at Risk

Pitcher's Thistle

Cirsium pitcheri

What is the Pitcher's thistle?

A close-up of Pitcher’s thistle flowers.
Pitcher's thistle blossoms once, then dies once the flowers have gone to seed.
© Parks Canada / Dr. John Morton

Pitcher's thistle is a whitish-green plant that lives only in the sand dunes of the upper Great Lakes.

This pretty plant has a slender, white, wooly stalk about 1 metre in height. When not flowering, it grows in a low ring of leaves, forming a rosette shape. It has a downy appearance and the fine white hairs that cover its leaves make it less prickly than other thistles.

Pitcher's thistle blossoms only once, between the ages of 2 and 10. Beautiful, pale pink or whitish flowers-anywhere from 2 to 125 of them-appear at the top of the stalk. The flowers produce seeds that are spread by the wind. After going to seed, the original plant dies. Species at Risk - Who Knew?

Pitcher's Thistle was named after Dr. Zina Pitcher, a 19th century American medical doctor and botanist. He first documented the plant in 1827.

Where is Pitcher's thistle found?

The largest part of the Pitcher's thistle range is in the state of Michigan, where there are at least seven populations of over 10,000 plants.

Although more than 25% of the geographic range of Pitcher's thistle lies in Canada, we host less than 10% of the total population. In Canada, Pitcher's thistle is endemic to the sand dunes of Lake Huron and Lake Superior. This means it is only found in these areas. There are only about 10,000 plants in Canada at about 23 known sites, most of which are on Lake Huron.

A map of Pitcher’s thistle locations in Canada.
The most northerly population of Pitcher's thistle in the world is in Pukaskwa National Park on Lake Superior.
© Parks Canada

Pukaskwa National Park of Canada on Lake Superior is home to the most northerly population of Pitcher's thistle in the world. The park has two natural Pitcher's thistle colonies, as well as one colony created by the transplantation of seeds.