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2020 Workshop Dates - all classes offered online (click on links to sign up)

June 16, 6:00 pm - 8:00 pm
June 24, 6:00 pm - 8:00 pm
July 2, 6:00 pm - 8:00 pm 

What is knotweed and how can I get rid of it?

Knotweed is a major problem in King County. This non-native, noxious weed chokes out native vegetation, increases erosion, degrades water quality and hurts habitat for fish and wildlife. It can also damage roads, pipes and building foundations.

This workshop teaches participants:

  • How invasive knotweed grows and spreads
  • How, when and where to control knotweed
  • What is being done to fight knotweed on rivers in King County
  • How to use and borrow a stem injector for use on your own land
  • What opportunities for habitat restoration may be available for your own land

These online workshops are free and open to the public. Click on the class date above to register. WSDA Pesticide Recertification credits will be available (2 credits pending).

After you take the class, you can sign up to borrow our knotweed stem injectors for your own knotweed projects!

Can't take a class, but want to borrow a stem injector? No problem. Watch our videos and take a quiz to qualify instead.

For more information contact us by email or phone at 206-477-9333.

worker injecting invasive knotweed - click for more information on knotweed

Related information

Related agencies


Program offices are located at 201 S. Jackson St., Suite 600, Seattle, WA 98104. To contact staff, see the Noxious Weed Control Program Directory, send an email, or call 206-477-WEED (206-477-9333).