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Oregon Noxious Weed Classification

Class A – a weed of known economic importance which occurs in the state in small enough infestations to make eradication or containment possible; or is not known to occur, but its presence in neighboring states make future occurrence in Oregon seem imminent.  Recommended action: Infestations are subject to eradication or intensive control when and where found.

Class B – a weed of economic importance which is regionally abundant, but which may have limited distribution in some counties. Recommended action: Limited to intensive control at  the state, county or regional level as determined on a site specific, case-by-case basis. Where implementation of a fully integrated statewide management plan is not feasible, biological control (when available) shall be the primary control method.

Class C – a priority noxious weed designated by the Oregon State Weed Board as a target for which the ODA will develop and implement a statewide management plan. “C” designated noxious weeds are species selected from either the “A” or “B” list.


View a Map of Nationwide CWMA's Below

CWMA Map - North American Invasive Species Network (


More Resources Below- Including Noxious Weed Brochures, Risk Assessments, Economic Analysis & More!

State of Oregon: Weeds and WeedMapper - Resources