Washington County, OR Landscaping Rules: Weed Ordinances (2026)

Washington County Code authorizes abatement of overgrown vegetation, noxious weeds, and fire-fuel grasses under ORS 105.550-105.570 and the county nuisance ordinance. The Sheriff's Office and Code Enforcement (part of Land Use & Transportation) handle complaints on unincorporated properties. Typical grass-height trigger is 10-12 inches on urbanized residential lots; vacant lots receive notice each late spring as growth accelerates in the Willamette Valley's wet climate. Oregon Department of Agriculture maintains the state noxious weed list (English ivy, Himalayan blackberry, tansy ragwort, Scotch broom, giant hogweed) and Washington County SWCD runs weed-pull programs. Cities adopt overlapping rules: Beaverton BC 5.15, Hillsboro HMC 5.08, Tigard TMC 6.02, Sherwood Municipal Code 8.16. Notice periods generally run 10-14 days; non-compliance results in county/city contractor abatement with costs placed as a lien on the property tax roll. Along the Tualatin River and its tributaries, riparian vegetation is protected by CWS (Clean Water Services) Design & Construction Standards and cannot be cleared without coordination.