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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

Scotch Thistle

Onopordum acanthium

This thistle is a large biennial plant growing up to 12 feet tall!

Reproduces through prolific seed production.

The stems have broad, spine-tipped wings.

Leaves are covered with a fine gray hair giving the plant a grayish-green color.

Flowers are large, violet to reddish and have numerous large, spiny bracts at the base.

Scotch thistle can form dense stands that are impenetrable to wildlife, livestock, and people. Most of the scotch thistle in Natrona County is found north of the Platte River, near the Johnson County line, and in the Midwest area.


Chemical control should be done at the rosette stage. 2,4-D and glyphosate can be used on rosettes. Contact your local weed and pest for more recommendations.


Cut off or dig up below ground level before seed production.