This is an annual or biennial plant growing to 2 feet tall.
It spreads by seed, often in winter when dried plants break off and tumbles in the wind.
Leaves are grayish-green, alternate, and upper leaves are very reduced.
Flowers are single, white or sometimes pinkish. Flower bracts are spiny.
Stems and leaves are covered with fine hairs.
Diffuse knapweed is exotic from Asia and can seriously reduce production potential of rangeland for for wildlife and livestock. In Natrona County is is mainly found in the southern Bighorn Mountain foothills .
Chemicals must be applied before the plant produces seed to be effective. Contact your local weed and pest for specific chemical recommendations.
There are currently seven species of biocontrol insects released on this plant in Natrona County.
Cut, pull, or dig up before seed production.