Knotweed is a Class B noxious weed in Washington State. Knotweed can spread rapidly in riparian areas since it lacks natural predators and has been present in many local watersheds for nearly a century.

Knotweed clones can significantly alter an ecosystem, displacing native streamside vegetation and contributing to bank erosion, which impacts water quality and degrades important habitat for fish and wildlife. If you need help removing knotweed, contact your local weed board!