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Noxious weeds

King County, Washington

To offer a suggestion or report an error on the King County Noxious Weeds website, please contact Sasha Shaw, education specialist.

Class Schedule

Register for a class

What is Knotweed and How Can I Get Rid of it?

All sessions are from 6:30 pm to 8:30 pm and have the same agenda:

Cost: Free (pre-registration required)
How to sign up: Register online
Credits: WSDA Pesticide License Recertification Credits will be available (2 credits)

Invasive knotweed is one of the toughest weeds around and it is becoming all too common in King County. It chokes out everything else, increases erosion and overwhelms riverbanks. Fighting it is frustrating without effective methods and tools. This workshop will explain why this plant is so tough to stop and what it takes to control it.


  • How invasive knotweed grows and spreads
  • How and where to use different methods to control knotweed
  • How to borrow a knotweed stem injector for use on your own land
  • What is being done to fight knotweed on rivers in King County

Staff from the King County Noxious Weed Control Program will teach how to identify knotweed, how and where it grows, and how to control it effectively using a variety of different methods. This is a hands-on workshop with practical control tips. Participants will be eligible to borrow the program’s knotweed stem injectors for use on their own knotweed. 

The King County Noxious Weed Control Program offers workshops and presentations upon request for community groups, neighborhood councils, vegetation management professionals, volunteer events, garden clubs and a wide range of other groups. Please contact Sasha Shaw if you would like a presentation on invasive plants or noxious weeds for your group, staff or community.

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).