Widely distributed but controllable. High priority for control or eradication where possible.
Quick Facts
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Report on EDDMapSSquarrose Knapweed
Centaurea virgata
Overview
Squarrose knapweed is a perennial plant from the Middle East that invades rangelands and roadsides. It is particularly aggressive in semi-arid environments and can form dense stands that eliminate native vegetation. Its recurved bract tips help seeds attach to animals and vehicles for dispersal.
How to Identify
Perennial 1-2 feet tall. Pink to purple flower heads with distinctive recurved (squarrose) bract tips. Deeply lobed lower leaves. Very branchy growth form.
Control Methods
Herbicide treatment is the primary control method. Biological control agents are being researched. Competitive seeding after treatment.
Herbicide Recommendations
Picloram, clopyralid, or aminopyralid. Apply in spring or fall.
⚠️ Always read and follow pesticide label directions. Contact your county weed superintendent for site-specific recommendations. Permits may be required near water.
Need help managing this weed?
Skyline CWMA can connect you with technical assistance, cost-share programs, and licensed contractors for treatment on your property.
