Noxious Weed Act & Rule

Protecting Colorado's stunning landscapes is a team effort, and it all starts with the Colorado Noxious Weed Act! This vital state law is our primary defense against invasive plants that threaten our native ecosystems, farms, and ranches. By classifying and prioritizing harmful weeds, the act empowers landowners and local communities to take action. It provides the framework for everything from on-the-ground eradication projects to public education, ensuring we can all work together to keep Colorado beautiful, healthy, and resilient for generations to come.

• Protection of Resources: The primary goal of the act is to protect Colorado's natural resources, ecosystems, and agricultural land. By controlling noxious weeds, the state aims to preserve biodiversity, maintain healthy rangelands, and protect crop yields from invasive species that can outcompete native plants.
• Prevention of Spread: The act provides a legal framework for preventing the introduction and spread of noxious weeds. It recognizes that these weeds can cause significant economic losses and environmental damage if left unmanaged.

Colorado law empowers counties and municipalities to create and enforce their own noxious weed management plans, which can be more stringent than state regulations. This allows local communities to effectively address specific weed problems.

What are the responsibilities of counties under the Noxious Weed Act?

• Establish Weed Management Programs: Counties must create programs that align with state guidelines.
• Create Local Plans: They can develop specific plans and ordinances tailored to local threats.
  • Weed Plan Template for Local Entities
  • Integrated Weed Management Plan Handbook
• Appoint a Weed Manager: Each county must appoint a supervisor to oversee weed management activities and work with landowners.
• Enforce the Act: Counties have the authority to inspect land and issue control orders to landowners who are not in compliance.
• Collaborate with Landowners: A core function is to provide information, technical assistance, and resources to help landowners meet their legal obligations for weed control.

Noxious Weed Management Strategies

List B County Management plans can be found here. (To see a county's data, click on its individual tab at the bottom of the spreadsheet.)

List B Rotation Schedule

Here are the key terms used to describe different management strategies:

• Eradication means completely eliminating a noxious weed species in a specific area by preventing it from reproducing until its seed bank is gone.
• Elimination is the first step of eradication, where all existing plants of a specified noxious weed are destroyed. This is followed by continued efforts to remove new growth until the seed bank is depleted.
• Containment involves creating a managed buffer zone to prevent a noxious weed from spreading from infested areas (where suppression is used) into uninfested areas (where eradication is the goal).
• Suppression means using various management techniques to reduce the growth, spread, and negative effects of noxious weeds in an infested area.

The Act Classifies noxious weeds into four main lists to guide management priorities:

• List A Weeds: The objective for these weeds is eradication—removing them entirely from the state before they can take hold. 
• List B Weeds: These species are well-established in some areas of the state, but not all. The goal is to stop their spread and manage existing populations to prevent further infestation.
• List C Weeds: These are widespread and often unmanageable across large areas. The focus is on integrated management—using a combination of methods—to prevent their spread and minimize their economic and environmental impacts. 
• Watch List: The Colorado Noxious Weed Act includes a separate Noxious Weed Watch List, which serves as an early warning system for potential invasive plant threats. This list is not part of the mandatory List A, B, or C classifications, but it is a critical tool for proactive management. It includes species that are considered a high priority for observation and reporting.

The federal noxious weed list, managed by the USDA, includes non-native species that threaten the U.S. It focuses on preventing new introductions by controlling the transport of these plants across state and international borders.

Each state maintains a noxious weed list tailored to its specific ecological and agricultural needs. These lists, often broader than the federal one, require landowners to control certain weeds and categorize them by management strategies like eradication or suppression.

Local noxious weed lists are created by counties and cities to address specific weed problems in their area. These lists are the most restrictive and local governments are responsible for enforcing weed management on all public and private land within their jurisdiction.

Strategic Plan to Stop the Spread of Weeds

Noxious Weed Act Enforcement and Compliance Webinar