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The Colorado Weed Rule
The Colorado Weed Rule

​​​The Colorado Department of Agriculture's Noxious Weed Program is responsible for creating and updating the Colorado Noxious Weed Rule. The goals of the program are to: 

  • Prevent the introduction of new invasive plant species

  • Eradicate species with isolated or limited populations 

  • Contain and manage those invasive species that are well established and widespread in Colorado

The Weed Rule is used to implement strategies to accomplish these objectives.

As of 2003, the Weed List was reformatted into 3 Lists:

  1. A List Weeds
    These weeds warrant mandatory eradication because there are very few of them in the state. The idea is to prevent these weeds from getting a stronghold in Colorado by rapidly responding and quickly controlling these species.

  2. B List Weeds
    These weeds are well established in some areas of the state but not in others. Every year, the State Weed Program writes management plans for select List B species, designating areas of the state for eradication, suppression and containment. In order to implement a coordinated effort, the management plans call for specific timelines and recommend control methods.

  3. C List Weeds
    These species are widespread throughout the State and are here to stay. They can be a high priority for Parks, due to interference with visitor experience.

Stay up to speed on the Weed Rule by visiting the State Weed Program regularly. The rule changes every year, as new management plans are written for List B species. The process begins in September with the statewide mapping of specific species and continues through March. New rules go into effect every May.

Colorado State Parks Resource Stewardship contributes to the statewide mapping of noxious weed species and supports the State Weed Program's objectives.