Minnesota Wildflowers


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Cirsium arvense (Canada Thistle)

Plant Info
Also known as: Field Thistle
Genus:Cirsium
Family:Asteraceae (Aster)
Life cycle:perennial
Origin:Europe
Status:
  • Invasive - ERADICATE!
  • Noxious Weed
  • Prohibited or Restricted species
Habitat:sun; old fields, along roads, waste areas
Bloom season:June - October
Plant height:3 to 5 feet
USDA PLANTS database:Minnesota county distribution map

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Detailed Information

Flower: Flower shape: indistinct Cluster type: round

[photo of flowers] Flower heads are ¾ inch across, lavender to pale pink or sometimes white. The bracts are flat, except for the tip which peels back away from the flower head. The bract tips are pointed, but not spined, and often a purplish color. One plant can have numerous flower heads, branching off the main stem near the top of the plant.

Leaves and stem: Leaf attachment: alternate Leaf type: lobed

[photo of leaves] Leaves are up to 6 inches long with no leaf stem and yellow spines scattered along the wavy edges. The lower leaves are up to 2½ inches across and deeply lobed, with a spine at the tip of each lobe. The upper leaves are more narrow, and generally more toothed than lobed. Leaves may be somewhat hairy on the underside. The main stem is light green, slightly ridged and may have scattered hairs but is not usually spiny.

Notes:

Canada Thistle is on the prohibited noxious weed list for Minnesota. It can form large colonies and crowd out native plants. Canada Thistle is fairly easy to identify from the numerous small flower heads, and bracts that have no spines.

Where to buy native seed and plants

Map of native plant purveyors in the upper midwest

Help support this site by buying seeds & plants from these vendors. Tell them we sent you!

  • Sunrise Native Plants - Adding Balance to Your Landscape
  • Morning Sky Greenery - Native Prairie Plants
  • Prairie Restorations - Bringing people together with the land
  • Shop for native seeds and plants at PrairieMoon.com!
  • Shooting Star Native Seeds - Native Prairie Grass and Wildflower Seeds

More photos

Photos taken at Long Lake Regional Park, New Brighton, MN, June 2006 and June 2007

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Jody in Manitoba
on: 2010-03-20 18:50:26

Once again Canada gets the blame, first it's our weather and now the weeds. Actually, Canada thistle is not native to Canada at all, and actually came across to canada with the first Eurpean settlers. It is native to Europe and Africa, therefore an invasive species.

Posted by: K. Chayka
on: 2010-03-20 21:38:14

Don't get down about it... It's only called Canada thistle because it invaded Canada first!

Posted by: Amy in Villa Park, Roseville, Ramsey County
on: 2012-07-03 20:52:32

Spotted this today around the water in the park

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For info on subjects other than plant identification (gardening, invasive species control, edible plants, etc.), please check the links and invasive species pages for additional resources.



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Note: Comments or information about plants outside of Minnesota and neighboring states may not be posted because I’d like to keep the focus of this web site centered on Minnesota. Thanks for your understanding.