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You are here: Home / Plants / Species Profiles / Diffuse Knapweed
Species Profiles

Diffuse Knapweed

Diffuse Knapweed

Scientific name: Centaurea diffusa Lam. (ITIS)

Synonym: Acosta diffusa (Lam.)

Common names: Diffuse knapweed, white knapweed, spreading knapweed, tumble knapweed

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Selected Resources

Native To: Eastern Mediterranean region (Wilson and Randall 2005)

Date of U.S. Introduction: 1800s (Wolfson et al. 2005)

Means of Introduction: Introduced accidentally through contaminated seed (Zouhar 2001)

Impact: Crowds out native species (Wilson and Randall 2005)

Current U.S. Distribution:


Selected Resources:

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Fact Sheet: Diffuse Knapweed (Jan 2014; PDF | 650 KB)
Alberta Invasive Plants Council (Canada).


Invasive Plant Atlas of the United States - Diffuse Knapweed
University of Georgia. Center for Invasive Species and Ecosystem Health.

Invasive Species Compendium - Centaurea diffusa
CAB International.

Plantwise Knowledge Bank - Diffuse Knapweed (Centaurea diffusa)
CABI. Plantwise.

Global Invasive Species Database - Centaurea diffusa (herb)
World Conservation Union. Invasive Species Specialist Group.


Germplasm Resources Information Network (GRIN) - Centaurea diffusa
USDA. ARS. National Genetic Resources Program.

Biology and Biological Control of Knapweed (Apr 2005, 3rd Ed; PDF | 2.85 MB)
USDA. FS. Forest Health Technology Enterprise Team.

Fire Effects Information System (FEIS) - Centaurea diffusa
USDA. FS. Rocky Mountain Research Station. Fire Sciences Laboratory.

PLANTS Database - Diffuse Knapweed
USDA. NRCS. National Plant Data Center.

Guide to Weeds in British Columbia - Diffuse Knapweed
British Columbia Ministry of Agriculture Food and Fisheries (Canada).


Encycloweedia: Data Sheet - Centaurea genus
California Department of Food and Agriculture.
Included on California's noxious weed list; see Encycloweedia: Program Details for additional resources.

Diffuse Knapweed Identification and Management (Aug 2008; PDF | 1.56 MB)
Colorado Department of Agriculture. Conservation Services Division.

Diffuse Knapweed - Best Management Practices Weed Profile (PDF | 213 KB)
Colorado State Parks.

Diffuse Knapweed (Centaurea diffusa)
Wisconsin Department of Natural Resources.

Class B Noxious Weed: Diffuse Knapweed
Washington State Noxious Weed Control Board.

Best Management Practices: Diffuse Knapweed (Jan 2010; PDF | 212 KB)
King County (Washington). Noxious Weed Control Program.


Weed Control in Natural Areas in the Western United States: Diffuse Knapweed (2013; PDF | 236 KB)
University of California. Weed Research and Information Center.

Diffuse and Spotted Knapweed
Colorado State University. Cooperative Extension.

Spotted and Diffuse Knapweed - Noxious Weeds of Nebraska (PDF | 1.11 MB)
University of Nebraska - Lincoln. Cooperative Extension.

Know Your Knapweeds (PDF | 153 KB)
North Dakota State University. Extension Service.


Diffuse Knapweed
Colorado Weed Management Association.

Weed Identification - Diffuse Knapweed
Montana Weed Control Association.


Integrated Taxonomic Information System. Centaurea diffusa. [Accessed Sep 10, 2014].

Wilson, L.M. and C.B. Randall. 2005. Biology and biological control of knapweed (PDF | 2.96 MB) (FHTET-2001-07) Morgantown, West Virginia: U.S. Forest Service Forest Health Technology Enterprise Team.

Wolfson, B.A., T.E. Kolb, C.H. Sieg, and K.M. Clancy. 2005. Effects of post-fire conditions on germination and seedling success of diffuse knapweed in northern Arizona. Forest Ecology and Management 216(1-3):342-358.

Zouhar, K. 2001. Centaurea diffusa. In: Fire Effects Information System. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.

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Last Modified: Nov 18, 2015
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