diffuse knapweed

Asterales > Asteraceae > Centaurea diffusa Lam.
Synonym(s): white knapweed

Diffuse knapweed is an annual, biennial, or short-lived perennial that is 8-40 in. (20-101.6 cm) tall. The basal leaves are lobed and stalked. The leaves become sessile, smaller, and less divided as they move up the stem. Flowering occurs from July to September, when white flowers develop in urn-shaped heads, in clusters, at the ends of the branches. The heads are subtended by leathery bracts. The lower and middle bracts have brown margins with spreading spines at the tips. Diffuse knapweed is native to southern Europe and north central Ukraine and prefers well-drained soils, roadsides, gravel pits, pastures and trails.


Identification, Biology, Control and Management Resources


Selected Images from Invasive.org

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Foliage; rosette
Richard Old, XID Services, Inc., Bugwood.org
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Seedling(s);
Richard Old, XID Services, Inc., Bugwood.org
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Flower(s);
USDA APHIS PPQ Archive, USDA APHIS PPQ, Bugwood.org
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Flower(s);
Cindy Roche, , Bugwood.org
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Flower(s);
Steve Dewey, Utah State University, Bugwood.org
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Plant(s);
Richard Old, XID Services, Inc., Bugwood.org
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Plant(s);
Sara Rosenthal, USDA Agricultural Research Service, Bugwood.org
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Plant(s);
Steve Dewey, Utah State University, Bugwood.org
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Management; Prescribed burn
Steve Dewey, Utah State University, Bugwood.org
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Control; burning; south of Shoshone, Idaho
Steve Dewey, Utah State University, Bugwood.org
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Invasive Reference(s):

Check Invasive.org for most current lists.
  • Arizona - Noxious Weed Law
  • California - Noxious Weed Law
  • Colorado - Noxious Weed Law
  • Montana - Noxious Weed Law
  • Nebraska - Noxious Weed Law
  • New Mexico - Noxious Weed Law
  • Nevada - Noxious Weed Law
  • North Dakota - Noxious Weed Law
  • Oregon - Noxious Weed Law
  • South Dakota - Noxious Weed Law
  • Utah - Noxious Weed Law
  • Washington - Noxious Weed Law
  • Wyonming - Noxious Weed Law
  • Invasive Plants: Western North America
  • Invasive Plants of the Upper Midwest


External Links


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USDA Forest Service Bugwood University of Georgia