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.