Invasive Plants of Wisconsin

Cirsium arvense Author
Canada thistle
Family: Asteraceae
plants inflorescence leaves flower head fruit fruit
plants inflorescence leaves flower head fruit

fruit

 

Cirsium arvense is one of only three plant species designated as "noxious" in Wisconsin (local governments may choose to designate additional species). Leaves are alternate with spine-tipped lobes and the flowers are in heads with bracts that are acute at the tip, but usually do not form spines. The plants are often 1 to 1.5 meters tall and tend to form dense stands in abandoned fields. They are also found in many other sunny habitats, including lawns where they tolerate repeated mowing (but therefore are much shorter than suggested above).

distribution
known Wisconsin distribution

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