Classification and Ranking

Noxious Weed Ratings

A noxious weed is a plant that has been defined as a pest by law or regulation. If a plant is found to be detrimental or destructive and difficult to control or eradicate it can be designated as a noxious weed. These ratings reflect the view of the statewide importance of the pest, the likelihood that eradication or control efforts would be successful, and the present distribution of the pest within the state. The rating also designates the action recommended by the regulatory agency to manage the pest. California Department of Food and Agriculture and Nevada Department of Agriculture each separately rate weeds and maintain their own noxious weed lists.

Rating categories:

"A" Weeds are normally limited in distribution throughout the state; actively excluded from the state and actively eradicated wherever found.
"B" Weeds are more widespread throughout the state; actively excluded where possible. In California, control or exclusion action is at the discretion of the country agriculture commissioner.
"C" Weeds are generally widespread throughout the state; actively eradicated only when found in a nursery. Abatement or control at the discretion of the state quarantine officer (Nevada) or county agriculture commissioner (California).

To view the noxious weed lists, click on the links below:

Invasive Weed Inventory

The California Invasive Plant Council maintains an Invasive Plant Inventory which categorizes non-native invasive plants that threaten the state's wildlands. Categorization is based on an assessment of the ecological impacts of each plant. The Inventory represents the best available knowledge of invasive plant experts in the state but has no regulatory authority.