Widely distributed but controllable. High priority for control or eradication where possible.
Quick Facts
Report your sighting through EDDMapS to help us track and respond to new infestations.
Report on EDDMapSDiffuse Knapweed
Centaurea diffusa
Overview
Diffuse knapweed is a biennial or short-lived perennial from Eurasia that invades rangelands, roadsides, and disturbed areas. It produces allelopathic chemicals that inhibit native plant growth. At maturity, the plant breaks off and tumbles like a tumbleweed, spreading seeds widely.
How to Identify
Biennial or perennial 1-2 feet tall. White to pale pink flower heads with spiny bracts. Deeply lobed leaves. At maturity, the plant breaks off at the base and tumbles.
Control Methods
Biological control using seed-head flies is effective. Herbicide treatment for new infestations. Competitive seeding after treatment.
Herbicide Recommendations
Clopyralid, picloram, or aminopyralid. Biological control (Urophora flies) is recommended for established infestations.
⚠️ 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.
