The state weed law requires the Washington State Noxious Weed Control Board to develop a state weed list every year. The list is divided into three different classes of noxious weeds, reflecting different control priorities. Because prevention or control of early infestations is the most cost-effective, the highest priority goes to controlling noxious weeds with the most limited distribution, the lowest to those that are the most widespread. Over a hundred and forty plants are on the Washington State Weed List (PDF).
County weed boards are also required to develop their own list annually. The county weed list (PDF) must include the highest priority noxious weeds (Class A and B designates), but the county weed board may also select additional lower priority noxious weeds for mandatory control. The Board encourages citizens to help set reasonable local control priorities and policies by participating in the development of the county weed list during the annual public hearing, and by attending board meetings which are held every other month beginning in February.