Renton, WA Landscaping Rules: Weed Ordinances (2026)

Under Washington state noxious weed law (RCW 17.10) and the King County Noxious Weed Control Program, Renton property owners must control or eradicate certain listed invasive plants on their property. Class A weeds (new invaders) must be eradicated wherever found. Class B weeds must be controlled to prevent spread, and specific Class B designates such as tansy ragwort, spotted knapweed, and poison hemlock require active management in King County. Class C weeds are listed for education and local enforcement. Common problem weeds in Renton include Himalayan blackberry, English ivy, Scotch broom, Japanese knotweed, reed canarygrass, yellow archangel, and garlic mustard, many of which invade Cedar River greenbelt, May Creek corridor, and wetland areas. The King County Noxious Weed Board offers free site visits and identification. Renton Municipal Code 1-3-3 declares overgrown vegetation a nuisance abatable by the city. Riparian buffers and critical areas require special coordination because manual or targeted removal may be preferred over herbicide to protect salmon-bearing streams. The city works with WSU Extension and King Conservation District on weed management programs.