Class C noxious weeds are designated by the State Weed Board as noxious so any county within the state may control these weeds within the county if they desire. Snohomish County has chosen to control the following list of Class C noxious weeds. Control in Snohomish County is required.
(Except not listed as Class A or B, native species designated in WAC 16-750-015)
| English hawthorn | Crataegus monogyma |