spotted knapweed USDA PLANTS Symbol: CESTM
U.S. Nativity: Exotic
Habit: Forbs/Herbs
Centaurea stoebe ssp. micranthos (Gugler) Hayek

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Taxonomic Rank: Magnoliopsida: Asterales: Asteraceae
Synonym(s): bushy knapweed
Native Range: Europe (BAIL);

Spotted knapweed is an herbaceous biennial or perennial plant that invades open areas throughout most of the United States. Its name is derived from the black margins of the flower bract tips which give the flower heads a spotted look. A basal rosette of deeply lobed leaves is produced the first year. Rosette leaves are deeply lobed, petiolate and approximately 8 in. (20 cm) long. Flowering stems are 2/3- 4 ft. (0.2-1.2 m) tall and branched. Stem leaves are alternate and may be slightly lobed or linear. Leaves become smaller and less lobed toward the apex. Flowering occurs in the early summer. Flowers are purple to pink in color and occur on small flower heads. Spotted knapweed invades a wide variety of habitats including pastures, open forests, prairies, meadows, old fields, and disturbed areas. It displaces native vegetation and reduces the forage potential for wildlife and livestock. Spotted knapweed is native to Europe and western Asia. It was accidentally introduced into North America in contaminated alfalfa and clover seed in the late 1800s.

Identification, Biology, Control and Management Resources

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


Plant(s);
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Flower(s);
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
Additional Resolutions & Image Usage

Flower(s);
Norman E. Rees, USDA Agricultural Research Service - Retired, Bugwood.org
Additional Resolutions & Image Usage

Flower(s); Flower
John M. Randall, The Nature Conservancy, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Plant(s); Rosette
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Foliage;
John Cardina, The Ohio State University, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s);
Ken Chamberlain, The Ohio State University, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s);
Barry Rice, sarracenia.com, Bugwood.org
Additional Resolutions & Image Usage

Infestation;
John M. Randall, The Nature Conservancy, Bugwood.org
Additional Resolutions & Image Usage

Plant(s); in flower
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
Additional Resolutions & Image Usage

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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U.S. National Parks where reported invasive:
Badlands National Park (South Dakota)
Blue Ridge Parkway (North Carolina)
Colonial National Historical Park (Virginia)
Craters of the Moon National Monument (Idaho)
Dinosaur National Monument (Colorado)
Glacier National Park (Montana)
Grand Canyon National Park (Arizona)
Great Smoky Mountains National Park (North Carolina & Tennessee)
Harpers Ferry National Historical Park (West Virginia)
Indiana Dunes National Lakeshore (Indiana)
Minute Man National Historical Park (Massachusetts)
Redwood National Park (California)
Rocky Mountains National Park (Colorado)
Saint Croix National Scenic Riverway (Wisconsin)
Shenandoah National Park (Virginia)
Theodore Roosevelt National Park (North Dakota)
Yellowstone National Park (Wyoming)



Invasive Listing Sources:
California Invasive Plant Council
City of Ann Arbor Michigan Parks and Recreation
Connecticut Department of Environmental Protection
Connecticut Invasive Plant Working Group
Faith Campbell, 1998
Hoffman, R. & K. Kearns, Eds. 1997. Wisconsin manual of control recommendations for ecologically invasive plants. Wisconsin Dept. Natural Resources, Bureau of Endangered Resources. Madison, Wisconsin. 102pp.
Invasive Plant Council of New York State
Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
Kentucky Exotic Pest Plant Council
Maryland Cooperative Extension Service.  2003. Invasive Plant Control in Maryland. Home and Garden Information Center, Home and Garden Mimeo HG88. 4 pp.
Maryland Department of Natural Resources, 1994
Mid-Atlantic Exotic Pest Plant Council, 2005
Mid-Atlantic Exotic Pest Plant Council, 2005
National  Wildlife Refuge Association, Silent Invasion: A Call to Action from the National Wildlife Refuge Association, 2002. Washington DC. 17 pp.
New Jersey Department of Agriculture, Division of Plant Industry, 2004
Pacific Northwest Exotic Pest Plant Council, 1998
Pennypack Ecological Restoration Trust, Pennsylvania.
South Carolina Exotic Pest Plant Council
Tennessee Exotic Pest Plant Council
Virginia Department of Conservation and Recreation, 2009