Parks & Open Space is responsible for weed management on open space areas, certain agricultural leased lands, and designated county maintained roads. The invasive plant and weed management program is responsible for weed control on:
The Boulder County Integrated Weed Management program is managed pursuant to Article 5.5 of Title 35, Colorado Revised Statutes (C.R.S.), the Colorado Noxious Weed Act as amended Title 35. Agriculture (§§ 35-1-101 – 35-81-102) (The Act). The Act establishes the need and jurisdiction for statewide management of noxious weeds.
Boulder County implements The Act by setting forth management objectives, plans, methods, and practices that utilize a variety of techniques for overall integrated management of noxious weeds. In establishing a coordinated program for the integrated management of noxious weeds, the county intends to encourage and apply all appropriate and available management methods.
The goal of integrated weed management is to restore, improve, and maintain healthy, functioning ecosystems and economically viable agricultural lands through responsible, proactive, and adaptive management of noxious weeds in accordance with state law. Boulder County also has the goal to decrease the acres of land on which herbicides are applied over time.
The Integrated Weed Management Plan lays out the county’s goals, objectives, and strategies for noxious weed management on county-owned lands and private property:
Situated at the intersection of the Great Plains and the Rocky Mountains, Boulder County is endowed with extraordinary geological and biological diversity, a natural heritage that helps form the foundation for an exceptional quality of life. Promoting and protecting that biodiversity and environmental health are the core values that direct the plan. Poor soil health, invasive weeds, and environmental contamination pose a threat to these values. Additionally, the State of Colorado mandates and regulates noxious weed control throughout the state. Boulder County takes this stewardship mission seriously.
Boulder County updated its weed management plans and policies in 2024 after a year-long public planning process. Noxious weed control is a complex problem; while most people can agree that biological diversity and ecosystem health are worthy objectives, there can be disagreement on the best ways to achieve them.
Throughout the public engagement for the plan, the county received a large volume of public input, much of which expressed concerns about the use of herbicides on county-owned natural lands. The county shares these concerns and is committed to minimizing herbicide use.
Public input helped inform and shape the goals and implementation strategies in the Integrated Weed Management Plan, including a goal to reduce usage of herbicides.
Throughout the public engagement phase the county has received a large volume of public input through testimony at public meetings, survey responses, and comments through the online comment form. Much of this input expressed concerns about herbicide use. County staff appreciates the interest, passion, and time dedicated to this process by so many members of the public, and this input was key in shaping the different versions of the plan that were considered.
Herbicides scheduled to be applied to non-agricultural open space areas.
Herbicides scheduled to be applied using drones to non-agricultural open space areas.
Sign up to receive email or text notifications about scheduled drone herbicide applications. Notifications will be sent out on the Friday before the week of application.
The pesticide sensitive registry is for people who have or can obtain documentation of sensitivity to pesticide products from a licensed Colorado physician. Registration is handled by the Colorado Department of Agriculture.
Cheatgrass is a major concern and it is a goal to eliminate about 3,000 acres of cheatgrass infestations within High Biodiversity Areas located along the foothills by 2030. Boulder County is using all the tools permitted by the Integrated Weed Management Plan including piloting new tools like soil amendments. About 4,300 acres of cheatgrass infestation have been successfully treated since 2019.
The video below shows before-and-after photos of areas treated for cheatgrass infestation.
A range of pilot projects are being implemented to evaluate the effectiveness of select noxious weed management treatments and their applicability to natural lands.
In 2023, a pilot project began testing mechanical methods for removing Hairy willowherb at Pella Ponds, the location of one of the infestations of this Eradicate species. The pilot project testing the effectiveness of hand digging Hairy willowherb is a three-year volunteer pilot effort that began in 2023.
A steam weeding pilot project will be initiated at the Ron Stewart Preserve at Rabbit Mountain trailhead to test effectiveness of this tool for total and targeted vegetation management. If it is determined to be feasible and scalable, second priority locations are the Walker Ranch Loop and Ethel Harrold trailheads, followed by the LoBo Regional Trail.
Soil amendment for cheatgrass control in a High Biodiversity Area will be trialed at Walker Ranch. Test plots will be monitored and evaluated. If the method is determined to be effective and scalable, expansion to other locations will be evaluated.
Goat browsing for suppression of broadleaf noxious weeds will be evaluated for effectiveness and scalability through pilot projects at locations on the following properties:
All these properties fall outside the Bighorn sheep protection area.
Russian olive and tamarisk (salt cedar) are List B Species. These invasive trees are targeted for removal.
If you see noxious weeds on open space, please let us know.
The Community Planning & Permitting Department is responsible for enforcing compliance with noxious weed regulations in unincorporated Boulder County.
