bighead knapweed
(Centaurea macrocephala Puschk. ex Willd.)

Overview

Appearance

Centaurea macrocephala is a large, perennial herb that grows on sturdy root stock and can reach 5 ft. (1.5 m) tall. Various common names including Lemon Fluff, Globe Centaury and Pineapple Thistle.

Foliage

Broadly lance-shaped leaves with sharp, pointed tips are rough to the touch and up to 15 in. (38.1 cm) long at the base of the plant.

Flowers

Single, showy, bright yellow flower head at tops of stems. Bracts (found under the flower head) are golden brown and fringed. Flowering occurs from July to September.

Fruit

Reproduces by seed which can be spread by wind, passing animals, humans, vehicles or equipment. It can re-sprout from woody root crown.

Ecological Threat

Centaurea macrocephala will out-compete grasses and other forage species, reducing food sources for wildlife and livestock. It is very difficult to remove once established. It is native to Turkey.

Selected Images

Maps

Invasive Listing Sources

• Alberta Weed Control Act
• National Park Service, Mid-Atlantic Exotic Plant Management Team Invasive Plant List
• Pacific Northwest Exotic Pest Plant Council, 1998
• Washington Noxious Weeds
• WeedUS - Database of Plants Invading Natural Areas in the United States

References