Appearance
Centaurea nigra is a perennial plant that can grow from 1-3 ft. (0.3-0.9 m) tall.

Foliage
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.

Flowers
Flowering occurs from June to October when purple (rarely white) flowers appear in heads at the tips of the branches.

Fruit
Fruit is a tan, hairy achene 0.08-0.12 in. (2-3 mm) long, may have a small, dark pappus.

Ecological Threat
Centaurea nigra 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.

Selected Images

Maps

Invasive Listing Sources

• Alberta Weed Control Act
• California Noxious Weeds
• Invasive Plant Species of West Virginia
• National Park Service, Mid-Atlantic Exotic Plant Management Team Invasive Plant List
• New Hampshire Invasive Plant Species Watch List
• New Hampshire Invasive Species Committee. 2005. Guide to Invasive Upland Plant Species in New Hampshire. New Hampshire Department of Agriculture,  Markets and Food Plant Industry Division and New Hampshire Invasive Species Committee.
• Pacific Northwest Exotic Pest Plant Council, 1998
• Pennsylvania Department of Conservation and Natural Resources Invasive Plants
• Washington Noxious Weeds
• WeedUS - Database of Plants Invading Natural Areas in the United States
• West Virginia Native Plant Society, Flora West Virginia Project, and West Virginia Curatorial Database System, September 3, 1999
• Wisconsin Noxious Weeds
• Wisconsin's Invasive species rule – NR 40

References