Tansy. Everywhere in Clackamas county. It's in the ditches, it's on the sides of the freeways. As a landowner, I am required to remove this noxious weed, only to have it blown back into my fields, because the county is not controlling their right of way. Take a drive down S. Fischer's Mill Rd., or Hattan Rd. You will see the absolute explosion of tansy in the ditches.
Expert Reviewer
Samuel Leininger Clackamas Soil and Water Conservation District 4-County Cooperative Weed Management Area Columbia Gorge Cooperative Weed Management Area