| spotted knapweed |
USDA PLANTS Symbol: CESTM USDA ARS GRIN: 419663 ITIS: 501347 |
| Centaurea stoebe ssp. micranthos (Gugler) Hayek | |
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Taxonomic Rank: Magnoliopsida: Asterales: Asteraceae |
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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. |
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Identification, Biology, Control and Management Resources
- Weed of the Week - USDA Forest Service
- Know Your Knapweeds - North Dakota State University
- Invasive Plant Atlas of New England - University of Connecticut
- Fire Effects Information System - USDA Forest Service
- Element Stewardship Abstract - The Nature Conservancy
- Biological Control of Invasive Plants in the Eastern United States - USDA Forest Service
- Plant Invaders of Mid-Atlantic Natural Areas - National Park Service and U.S. Fish and Wildlife Service
- Biology and Biological Control of Knapweed - USDA Forest Service
- Weeds Gone Wild: Alien Plant Invaders of Natural Areas - Plant Conservation Alliance
- Program Aid - USDA APHIS PPQ
- Fact Sheet - Pennsylvania Dept. of Conservation and Natural Resources
| Selected Images from Invasive.org | View All Images at Invasive.org |
 Plant(s); James H. Miller, USDA Forest Service, Bugwood.org Additional Resolutions & Image Usage |
 Infestation; Steve Dewey, Utah State University, Bugwood.org Additional Resolutions & Image Usage |
 Plant(s); Steve Dewey, Utah State University, Bugwood.org Additional Resolutions & Image Usage |
 Stand; Field 20 miles east of Missoula Norman E. Rees, USDA Agricultural Research Service, Bugwood.org Additional Resolutions & Image Usage |
 Plant(s); Spotted knapweed plant, Centaurea stoebe ssp. micranthos (Centaurea maculosa), in bloom. L.L. Berry, , Bugwood.org Additional Resolutions & Image Usage |
 Infestation; Landscape view of extensive infestations of spotted knapweed, Centaurea stoebe ssp. micranthos (Centaurea maculosa), in bloom. L.L. Berry, , Bugwood.org Additional Resolutions & Image Usage |
 Fruit(s); Steve Hurst, USDA NRCS PLANTS Database, Bugwood.org Additional Resolutions & Image Usage |
 Fruit(s); Ken Chamberlain, The Ohio State University, Bugwood.org Additional Resolutions & Image Usage |
 Plant(s); James H. Miller, USDA Forest Service, Bugwood.org Additional Resolutions & Image Usage |
 Foliage; Ohio State Weed Lab Archive, The Ohio State University, Bugwood.org Additional Resolutions & Image Usage |
 Foliage; pubescence on the underside of young leaf. John Cardina, The Ohio State University, Bugwood.org Additional Resolutions & Image Usage |
 Foliage; John Cardina, The Ohio State University, Bugwood.org Additional Resolutions & Image Usage |
 Seedling(s); Ohio State Weed Lab Archive, The Ohio State University, Bugwood.org Additional Resolutions & Image Usage |
 Flower(s); John Cardina, The Ohio State University, Bugwood.org Additional Resolutions & Image Usage |
 Flower(s); Marisa Williams, University of Arkansas, Fayetteville, Bugwood.org Additional Resolutions & Image Usage |
 Flower(s); Marisa Williams, University of Arkansas, Fayetteville, Bugwood.org Additional Resolutions & Image Usage |
Taxonomic References:
- USDA, NRCS. 2001. The PLANTS Database, Version 3.1, National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
Invasive Listing Sources:
- City of Ann Arbor Michigan Parks and Recreation
- Connecticut Department of Environmental Protection
- Connecticut Invasive Plant Working Group
- Faith Campbell, 1998. Plants that Hog the Garden: Invasive Plants in the United States. Fine Gardening Online
- 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.
- 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
- Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
- Pacific Northwest Exotic Pest Plant Council, 1998
- Pennypack Ecological Restoration Trust, Pennsylvania.
- Virginia Department of Conservation and Recreation, 1999.
- WeedUS - Database of Plants Invading Natural Areas in the United States
- Arizona Noxious Weeds
- Arizona Noxious Weeds
- California Invasive Plant Council
- California Noxious Weeds
- California Noxious Weeds
- Colorado Noxious Weeds
- Colorado Noxious Weeds
- Connecticut Noxious Weeds
- Idaho Noxious Weeds
- Idaho Noxious Weeds
- Kentucky Exotic Pest Plant Council Significant Threat
- Massachusetts Noxious Weeds
- Massachusetts Noxious Weeds
- Michigan Noxious Weeds
- Michigan Noxious Weeds
- Montana Noxious Weeds
- Montana Noxious Weeds
- North Dakota Noxious Weeds
- North Dakota Noxious Weeds
- Nebraska Noxious Weeds
- Nebraska Noxious Weeds
- New Hampshire Noxious Weeds
- New Mexico Noxious Weeds
- New Mexico Noxious Weeds
- Nevada Noxious Weeds
- Nevada Noxious Weeds
- Oregon Noxious Weeds
- Oregon Noxious Weeds
- South Carolina Exotic Pest Plant Council Severe Threat
- South Dakota Noxious Weeds
- South Dakota Noxious Weeds
- Tennessee Exotic Pest Plant Council Significant Threat
- Utah Noxious Weeds
- Utah Noxious Weeds
- Washington Noxious Weeds
- Washington Noxious Weeds
- Wyoming Noxious Weeds
- Wyoming Noxious Weeds
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