By Amy Grotta, OSU Forestry & Natural Resources Extension – Columbia, Washington & Yamhill Counties
Like just about any small woodland, the Matteson Demonstration Forest has its share of invasive weeds. Besides familiar and ubiquitous foes such as Scotch broom and thistles, one of particular concern is knapweed.
With purple flowers emerging from roundish bases at the top of a tall stalk, knapweeds superficially resemble a sort of spineless thistle, and in fact they are relatives of thistles, botanically speaking. They are biennial (2-year life cycle) to perennial plants and reproduce by seed. Fairly inconspicuous in the winter and spring; at this time of year, their purple flowers betray their location on and along roadbeds and other disturbed areas. Continue reading