Species At Risk

Pitcher’s Thistle

(Cirsium pitcheri)


Pitcher’s Thistle
Pitcher’s Thistle occurrences map


The Pitcher’s Thistle is unlikely to be mistaken for the more common thistles of Ontario roadsides and old fields. The stem and leaves are slender and covered in fine, whitish fuzz. The main stem can be up to one metre in height, and the leaves are greyish-green and deeply divided into narrow, spine-tipped segments. This species may grow for many years before flowering. It eventually produces between two and 125 flowering heads, made up of many small pinkish or creamy-white flowers that provide a source of nectar for bees and other insects. The seeds have a downy white “parachute” and can be carried by the wind some distance from the parent plant.

Action we are taking:


The global population of the Pitcher’s Thistle is limited to the Great Lakes basin of Canada and the United States. In Canada, the Pitcher’s Thistle is found only in Ontario where it is believed to be restricted to 10 sites: two on the Lake Huron shoreline south of the Bruce Peninsula, one on the Georgian Bay shoreline, one on the Lake Superior shoreline and the remainder on Manitoulin Island.


The Pitcher’s Thistle grows in windblown sandy habitats, especially on coastal sand dune ridges, among grasses and other plants. It requires a moderate amount of sand movement, and open, bare areas among the vegetation.


The main threats to Pitcher’s Thistle are habitat loss and degradation as a result of urban development, excessive recreational use of beaches, including ATV use on sand dunes, and changes in normal sand build-up due to shoreline modifications. Natural factors, such as browsing by White-tailed Deer are also a threat to this thistle.


Pitcher’s Thistle is protected under Ontario’s Endangered Species Act and the federal Species at Risk Act.

What You Can Do to Pitcher’s Thistle

  • The Ministry of Natural Resources tracks species at risk such as Pitcher’s Thistle. You can use a handy online form to report your sightings to the Natural Heritage Information Centre. Photographs with specific locations or mapping coordinates are always helpful. nhic.mnr.gov.on.ca
  • Report any illegal activity related to plants and wildlife to 1-877-TIPS-MNR (847-7667).
  • Private land owners have a very important role to play in species at risk recovery. If you find Pitcher’s Thistle on your property, you may be eligible for stewardship programs that support the protection and recovery of species at risk and their habitats.
  • Volunteer with your local nature club or provincial park to participate in surveys or stewardship work focused on species at risk.
  • Pollinators, such as bees, are in steep decline across the globe and they play a key role in the survival of many of Ontario’s rare plants. For information on how you can help scientists monitor pollinator populations in Ontario visit: www.seeds.ca/proj/poll.
  • Invasive species seriously threaten many of Ontario’s species at risk. To learn what you can do to help reduce the threat of invasive species, visit: ontario.ca/invasivespecies ; www.invadingspecies.com ; www.ontarioinvasiveplants.ca ; and, www.invasivespecies.gc.ca .

Did you know?

Pitcher’s Thistle was named after Dr. Zina Pitcher, who discovered the plant while serving as an army surgeon during the 1820s at Fort Brady, Sault Ste. Marie on Lake Superior.

Did you know?

The Pitcher’s Thistle will grow without flowers for three to 11 years before flowering once and then dying.

Did you know?

The Pitcher’s Thistle can be confused with a common sand dune plant called Wormwood. Wormwood leaves are more finely divided, often purple at the base and have no spines.

Did you know?

The Pitcher’s Thistle has a delicate relationship with its sandy habitat. Partial natural burial in sand, which happens due to wind and storm events or human activities, stimulates growth of this plant, but too much can kill them.

The Endangered Species Act

Contact your local ministry office

Often the best source of local information on species at risk is your nearest ministry office. Call with your questions or concerns.