Invasive Plants and Weed Management on Open Space

Parks & Open Space is responsible for weed management on open space areas, certain agricultural leased lands, and designated county maintained roads.

Herbicide and Roadside Mowing

Planned Herbicide Applications

Herbicides scheduled to be applied to open space areas.

View Past Herbicide Activity

Daily Planned Roadside Mowing

Mowing scheduled along county maintained roads.

View Past Mowing Activity

Drone Herbicide Applications

Herbicides scheduled to be applied using drones to open space areas.

View Past Drone Activity

Email and Text Alerts

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.

Updated Boulder County Integrated Weed Management Plan

Boulder County updated its weed management plans and policies in 2024 after a year-long public planning process. 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:

Integrated Weed Management Objective: Boulder County restores, improves, and maintains healthy, functioning ecosystems and economically viable agricultural lands through responsible, proactive, and adaptive management of noxious weeds in accordance with state law.
Three broad strategies identify priorities: manage, collaborate and communicate, and protect health and safety. The plan provides details on the decision processes, tools and tactics employed to implement these strategies.

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 Integrated Weed Management Plan

Planning History and Events

Nov 19 – Board of County Commissioners
The Board of County Commissioners (BOCC) approved changes to the plan that they had asked staff to address at the May 23 meeting. Staff revised the plan consistent with the BOCC’s direction and the final document was approved.
Watch the Meeting
May 23 – Board of County Commissioners
The commissioners voted 2-1 to approve the Integrated Weed Management plan with changes. Changes will be incorporated to the plan and brought back to commissioners to be signed at a business meeting. Public comments were not accepted at the meeting.
Watch the Meeting
April 16 – Board of County Commissioners
Staff presented the Draft Plan Version 3.0. and the commissioners held a public hearing. The commissioners requested additional information to be provided for the May 23 meeting. The hearing adjourned at 8:35 p.m.
Watch the Meeting
March 28 – Parks & Open Space Advisory Committee
The committee voted 6-2 to recommend that the Board of County Commissioners approval the plan as presented by staff with the following amendments:
1) Add glyphosate to the list of herbicides no longer used.
2) Direct staff to create a multi-modal notification system and subscription notification system to notify residents of aerial spraying.
Watch the Meeting
March 12 – Panel Discussion on the State of Science for Integrated Weed Management
Boulder County held a held a paneled discussion on the state of science for integrated weed management.
Watch the Webinar
Feb. 22 – Parks & Open Space Advisory Committee
Staff from Jefferson County, Larimer County, and Rocky Mountain National Park presented their agency’s weed management practices. Staff presented a summary of proposed changes to the draft plan. Public comments were accepted at the meeting.
Watch the Meeting
Jan. 25 – Parks & Open Space Advisory Committee
Numerous public comments were made and the committee heard a presentation on goat grazing for weed management.
Watch the Meeting
Dec. 5 – Parks & Open Space Advisory Committee Study Session
Study session for in-depth Q&A between committee members and staff.
Watch the Meeting
Oct. 26 – Parks & Open Space Advisory Committee
Staff provided updates to the management plan.
Watch the Meeting.
Oct. 13 – Weed Management Tour
Oct. 11 – Open House and Community Discussion
Discussion Report
Oct. 2 – Draft plan, Story Map, and Survey Released
Sept. 28 – Parks & Open Space Advisory Committee
Staff provided updates on the management plan.
Watch the Meeting
Aug. 24 – Parks & Open Space Advisory Committee
Lisa Blecker, Colorado State University Administrator, Pesticide Regulatory Education Program, gave a presentation on the Pesticide Labeling, Safety, and Approval Process.
Watch the Presentation
Aug. 22 – Weed Management Tour
July 27 – Parks & Open Space Advisory Committee Site Visit
July 25 – Weed Management Tour
June 22 – Parks & Open Space Advisory Committee
Scott Nissen, Professor Emeritus at Colorado State University, gave a presentation on the Behavior of Cheatgrass.
Watch the Presentation

Previous Draft Plans

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.

Additional Resources

Integrated Weed Management FAQs: Staff’s responses to frequent comments made throughout the engagement process.
List A Weed Species Maps: Maps showing the locations of List A noxious weed species in Boulder County.
Relevant Research Studies: A list of scientific studies related to noxious weeds.
Story Map: Provides some important planning context and case studies of lands where integrated weed management has already been implemented.
Pitkin County Success Story: In four years, a 6-acre expanse transitioned from 26 percent native vegetation and heavily infested with cheatgrass to 81 percent native plants and barely any cheatgrass.
Written Public Comments: Written public comments were accepted Feb. 15 through May 23. Comments were reviewed by staff, Parks & Open Space Advisory Committee members, and the Board of County Commissioners.
Community Survey Results: A community survey was open from Oct. 2–19, 2023. The survey received 1,076 responses, including 555 open-ended responses. Questions were designed to solicit thoughts on weeds as threat to ecosystem health and their contribution to wild fire risk, and opinions about alternative weed management programs, ranging from no herbicide use to herbicides as the primary tool. Respondents were asked to refer to the initial draft plan and companion story map for more information and examples.

Management Practices

The invasive plant and weed management program is responsible for weed control on:

34,000 acres of land designated as natural areas.
120 miles of trail.
685 miles of county maintained road right-of-way.

Colorado State Regulatory Requirement

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.

Goals

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.

Strategies

Manage: Use integrated week management tools and best practices to improve and maintain ecosystem diversity and health by preventing the introduction of new noxious weed species, eradicating isolated or limited populations, containing, eliminating, and suppressing noxious weed species within the county, while decreasing the use of herbicides over time, and limiting the use of herbicides to the protection of areas of high biodiversity and to circumstances where cultural, mechanical, and biological tools are not effective or feasible.
Collaborate and Communicate: All entities can collaborate and communicate with neighbors, expert staff, partners, peer agencies, private property owners, and the public to improve noxious weed management throughout the county and region.
Protect Health and Safety: Follow equipment safety guidelines, herbicide application labels, and best management practices to protect the health and safety of staff, the public, and ecological values.

Documents

What You Can Do

Identify and do not plant them in your garden. If they already grow in your garden, remove them.
Report a Concern on private property.
Volunteer with Parks & Open Space
Educate friends and neighbors who have these plants growing on their properties. Their plants will likely spread to your property.
Minimize spread of weeds on open space by staying on the trails, feeding horses weed free hay, and cleaning weed seeds from your hiking boots or bicycle tires before recreating on open space property.

Additional Resources

Pesticide Sensitive Persons Registry

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.

Report Weeds

On Private Property

The Community Planning & Permitting Department is responsible for enforcing compliance with noxious weed regulations in unincorporated Boulder County.

Report a Concern