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Phone: 307-472-5559
Hours: 7:30am - 4:00 Monday-Friday
If you need assistance after hours: Please Call Brian Connely , 307-267-3848

Canada Thistle

Cirsium arvense

This plant is a colony forming perennial growing up to 4 feet tall.

Reproduces mainly through a massive spreading rootstock.
These roots have the ability to reproduce another plant from small, cut up pieces!

The alternate leaves are extremely variable: from oblong to lance-shaped and deeply divided into
spiny-tipped irregular lobes.

Flower heads are vase-shaped and purple to lavender.

Canada thistle is native to Eurasia and is now the most widespread noxious weed in the world! It is found on almost every continent. The reproducing roots make it impossible to control through cultivation or hand-pulling. It is found throughout Natrona County in landscaped residential habitats, rangeland riparian areas, and barrow ditches.


There are a variety of chemical control options for actively growing, bolting plants. Milestone can also be VERY effective on fall regrowth. Glyphosate (RoundUp) may be used on actively growing plants at bud stage. Speed Zone is labeled for thistles and may be used in turf or ornamentals. Contact your local weed and pest for specific recommendations.