squarrose knapweed USDA PLANTS Symbol: CEVI
U.S. Nativity: Exotic
Habit: Forbs/Herbs
Centaurea virgata Lam.

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Taxonomic Rank: Magnoliopsida: Asterales: Asteraceae
Native Range: central and southern Europe (BAIL);

Squarrose knapweed is a perennial forb that can grow 12-18 in. (30.5-45.7 cm) tall. The leaves are alternate and deeply dissected. Flowering occurs in early to mid-summer, when pink flowers develop in heads at the tips of the branches. This species is sometimes confused with diffuse knapweed (Centaurea diffusa), but can be distinguished from diffuse knapweed by the floral bracts. Bracts on squarrose knapweed are curved outward and are not laterally toothed. Squarrose knapweed is native to the Mediterranean region and occurs in open disturbed sites, such as rangelands, roadsides, and grasslands.

Identification, Biology, Control and Management Resources

Selected Images from Invasive.orgView All Images at Invasive.org


Plant(s); from the eastern Mediterranean region is spreading on rangelands in the western United States.
Steve Dewey, Utah State University, Bugwood.org
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Flower(s);
Steve Dewey, Utah State University, Bugwood.org
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Flower(s); seedhead
Cindy Roche, , Bugwood.org
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Flower(s);
Steve Dewey, Utah State University, Bugwood.org
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Plant(s); in flower
Steve Dewey, Utah State University, Bugwood.org
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Infestation;
Sara Rosenthal, USDA Agricultural Research Service, Bugwood.org
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Plant(s);
USDA Agricultural Research Service Archive, USDA Agricultural Research Service, Bugwood.org
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Plant(s);
USDA Agricultural Research Service Archive, USDA Agricultural Research Service, Bugwood.org
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Infestation;
Steve Dewey, Utah State University, Bugwood.org
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Infestation;
Steve Dewey, Utah State University, Bugwood.org
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Plant(s); post-fire emergence
Steve Dewey, Utah State University, Bugwood.org
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Flower(s);
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
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EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org
 


State(s) Where Reported invasive.
Based on state level agency and organization lists of invasive plants from WeedUS database.

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Invasive Listing Sources:
Faith Campbell, 1998
Pacific Northwest Exotic Pest Plant Council, 1998