| black knapweed | USDA PLANTS Symbol: CENI2 U.S. Nativity: Exotic Habit: Forbs/Herbs |
| Centaurea nigra L. |
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Taxonomic Rank: Magnoliopsida: Asterales: Asteraceae |
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| Synonym(s): black knapweed | |
| Native Range: Europe (BAIL); | |
Black knapweed is a perennial plant that can grow from 1-3 ft. (0.3-0.9 m) tall. Leaves, near the base, are petiolate, oblanceolate, shallowly dentate and 2-10 in. (5-25 cm) long. As leaves move up the stem, they become smaller, sessile, linear, and entire. Flowering occurs from June to October, when purple (rarely white) flowers appear in heads at the tips of the branches. Bracts that subtend the flower head are dark brown to black with numerous wiry lobes along the margins. Black knapweed is native to Europe and was first found in the United States in 1895 in Pullman, Washington. Preferred habitat includes roadsides, waste places, fields and clearings. |
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| Selected Images from Invasive.org | View All Images at Invasive.org |
 Plant(s); in flower Cindy Roche, , Bugwood.org Additional Resolutions & Image Usage |
 Plant(s); Bruce Ackley, The Ohio State University, Bugwood.org Additional Resolutions & Image Usage |
 Plant(s); Bruce Ackley, The Ohio State University, Bugwood.org Additional Resolutions & Image Usage |
 Seedling(s); Joseph M. DiTomaso, University of California - Davis, Bugwood.org Additional Resolutions & Image Usage |
 Flower(s); seedhead Cindy Roche, , Bugwood.org Additional Resolutions & Image Usage |
 Flower(s); all flowers same length Joseph M. DiTomaso, University of California - Davis, Bugwood.org Additional Resolutions & Image Usage |
 Seed(s); Bruce Ackley, The Ohio State University, Bugwood.org Additional Resolutions & Image Usage |
 Seed(s); Bruce Ackley, The Ohio State University, 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 Alternative content
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 State(s) Where Reported invasive. Based on state level agency and organization lists of invasive plants from WeedUS database. Alternative content
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| Invasive Listing Sources: |
| Faith Campbell, 1998 |
| Pacific Northwest Exotic Pest Plant Council, 1998 |
