Weeds - Diffuse Knapweed

Photo: Diffuse KnapweedDiffuse Knapweed is a biennial single-stemmed plant with numerous lateral branches. Flowers are white to rose, or occasionally purplish. The flowerheads are slender with pointed, fringed bracts.

Diffuse Knapweed will form dense stands on any open ground, excluding more desirable forage species. Once established, the necessary extensive control measures are often more expensive than the potential income of the land.

Test plots by the OSU Extension Service have shown that residual chemicals are preferable when trying to control the weed. Picloram (Tordon 22K), dicamba (Banvel), 2,4-D LV and Amine are effective. Always read and follow the label. Biological controls are increasing, check with local weed control personnel for more information.