California Department of Transportation

Noxious And Invasive Plants and Seed

Erosion Control Planting

This page provides an overview of noxious and invasive plant regulations, together with links to more detailed information.

Noxious Seed and Plant Species Guidance

Noxious plant species control in the State of California is directed by the California Department of Food and Agriculture (CDFA). CDFA is primarily concerned with the threat that noxious plant species pose to agricultural activity. Noxious weed seed includes both prohibited and restricted noxious weed seed as defined California Food and Agricultural Code California Seed Law Sections 52257 and 52258. By state law, seed lots cannot be sold when they contain any prohibited noxious weed seeds. Caltrans specifications also limit common (non-noxious) weed seed to less than 1.0 percent by weight.

For an exhaustive overview of California law regarding seed use, including detailed definitions of "weed seed," please click the link below:

California Noxious Plant List

The official list of noxious weeds for the state of California is the California Department of Food and Agriculture (CDFA) "A Rated" list. Local county agriculture commissioners can add plants to the "B Rated" and "C Rated" portions of this list. Please note that the "noxious" classification of a plant is ecosystem or climate zone specific. For example, a plant considered noxious in a coastal climate may not be considered noxious in an arid portion of the state. The list linked below may be used both to help identify specific weed species to be removed on a project site, as well as to help identify plant species that ought to be avoided, or used with caution in limited locations.

Invasive Species Guidance

Federal agencies will not fund work that contributes to the introduction or spread of invasive species unless all reasonable measures to minimize risk have been considered. Consequently, Federal funds cannot be used for construction, revegetation, or landscaping activities that include invasive plant species. The Federal government has delegated the creation and maintenance of invasive species lists to the various State governments.

In California, the Invasive Species Council of California (ISCC) represents the highest level of leadership and authority in state government regarding invasive species. The ISCC is an inter-agency council that helps to coordinate and ensure complementary, cost-efficient, environmentally sound and effective state activities regarding invasive species. More detailed information regarding ISCC is provided below.

FHWA Invasive Species Guidance

For specific information regarding Federal Invasive Species Guidance, please click the link below:

California Invasive Plant List

The Invasive Species Council of California (established February 2009) recently asked the California Invasive Species Advisory Committee to create a list of “invasive species that have a reasonable likelihood of entering or have entered California for which an exclusion, detection, eradication, control or management action by the state might be taken". The Invasive Species List linked below is the product of this committee. Plants included in this list ought to be used with caution - and only after verifying that the particular conditions of the project site - climate, exposure, soils, prevailing winds, etc. will not cause the uncontrolled spread of the plant. For example a particular plant included in the invasive plant list may be well suited for an urban environment, but might pose an invasive risk used in a more natural environment.