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Learn how to control invasive knotweed at free King County Noxious Weed Program workshops


Invasive knotweed can be a challenging foe for property owners, and the King County Noxious Weed Program offers free assistance to anyone who is battling this hard-to-conquer plant.


Homeowners who have struggled to control invasive knotweed know thatknotweed_leaves this is no ordinary, garden-variety pest.

The King County Noxious Weed Program has scheduled a series of knotweed control workshops for June and July, where property owners can learn safe and effective control methods that can eliminate this troublesome species. Workshop participants will be eligible to borrow the county’s knotweed stem-injectors for use on their own land, at no cost.

Workshops are scheduled for:

• June 16, Covington Library, 27100 164th Ave. SE, Covington
• June 23, Enumclaw Library, 1700 First St., Enumclaw
• July 14, Tukwila Community Center, Room B, 12424 42nd Ave. S., Tukwila
• July 21, Renton Highlands Library, 2902 NE 12th St., Renton
• July 23, Meadowbrook Farm, 1711 Boalch Ave., North Bend

Workshop participants will learn practical information on how to effectively get rid of knotweed, which is a bright green, bamboo-like plant that is conspicuous this time of year along King County roads and rivers, and in numerous backyards and parks. Attempts to control knotweed often result in frustration because of the plant’s tenacity and its tendency to grow in difficult places to access.

According to Justin Bush, King County Noxious Weed Program riparian project manager, the county has been fighting knotweed along rivers for the past 12 years with help from state and federal grants, partnerships with conservation groups, other public agencies and private landowners.

“Invasive knotweed does not respect property lines and has devastating impacts to King County’s most sensitive and high value areas,” Bush said. “Removing knotweed improves habitat for fish and wildlife, and protects streambanks from erosion and failure.”

Bush said cooperation amongst landowners is a key to controlling knotweed, because the plant spreads easily from one property to another by root and stem fragments and creeping underground roots.

To sign up for a class or for more information, visit or call the noxious weed program at 206-477-WEED (206-477-9333).

Information on noxious weeds, including the King County weed list and the Washington noxious weed law can be found online at For more information on the King County Noxious Weed Board and Noxious Weed Program, call 206-477-WEED (206-477-9333) or email