Invasive Plants & Weed Management on Open Space
Open space

Invasive Plants & 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.

Management Plan Update

Herbicide & Roadside Mowing

Management Practices

Report Weeds

Boulder County Integrated Weed Management Plan

Boulder County is updating its current weed management plans and policies. Currently, the county is operating with two plans: the Boulder County Noxious Weed Management Plan and the Boulder County Parks & Open Space Weed Management Policies and Procedures. These two documents will be combined into a single Integrated Weed Management Plan.

The initial Draft Integrated Weed Management Plan was released on Oct. 2, 2023. Staff are working on an updated plan based on public feedback and input from the Parks & Open Space Advisory Committee (POSAC). Updates will include:

Proposed Changes

A summary of proposed changes will be presented at the Feb. 22 Parks & Open Space Advisory Committee (POSAC) meeting. Changes include:

  1. New Goal: Reduce herbicide applications on open space natural lands by 50% by 2030. The implementation plan appendix will provide details.
  2. Revised aerial spray policy: Remove aerial spraying by helicopter. Maintain option to use drone applications in limited circumstances, to be laid out in the implementation appendix.
  3. Limit glyphosate.
  4. Expand use of alternative tools, such as steam weeding, goat grazing, and novel soil amendments (e.g., Nutrafix).
  5. Format changes: to simply the plan.
  6. Added appendix will lay out the proposed three-year implementation on county natural lands, including maps of treatment areas and proposed methods.

More details can be found in the Summary of Proposed Changes document.

See Integrated Weed Management FAQs for responses to comments received.

Written Public Comments

Submit your comments regarding the Integrated Weed Management Plan. Comments will become part of the public record, including your name and city, and will be available for everyone to see. Comments are subject to the Social Media Comment Policy. Comments will be reviewed by staff, Parks & Open Space Advisory Committee members, and the Board of County Commissioners.

Submit Written Comments

View submitted comments

Upcoming Meetings

  • March 12 – Panel Discussion on the State of Science for Integrated Weed Management
    Boulder County will hold a webinar from 6:30-8:30 p.m. Questions from the public will be welcomed and registration is required. Learn more
  • March 28 – Parks & Open Space Advisory Committee
    Staff will present the revised draft plan. Committee members will deliberate and make a recommendation to the Board of County Commissioners. Public comments will be accepted.
  • April 16 – Board of County Commissioners
    The commissioners will hold a public hearing. Public comments will be accepted.
  • May 21 – Board of County Commissioners
    The commissioners will deliberate and make a decision. Public comments will not be accepted.

Previous Events

  • 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.
  • Jan. 25 – Parks & Open Space Advisory Committee
    Numerous public comments were made and the committee heard a presentation on goat grazing for weed management.
  • Dec. 5 – Parks & Open Space Advisory Committee Study Session
    Study session
    for in-depth Q&A between committee members and staff.
  • Oct. 26 – Parks & Open Space Advisory Committee
    Staff provided updates to the management plan.
  • Oct. 13 – Weed Management Tour
  • Oct. 11 – Open House and Community Discussion
  • Oct. 2 – Draft plan, Story Map, and Survey Released
  • Sept. 28 – Parks & Open Space Advisory Committee
    Staff provided updates on the management plan.
  • 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.
  • 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.
  • Jan. 25 – Parks & Open Space Advisory Committee
    Jordan Sarazen of Goat Bros Grazing gave a presentation on goat grazing for weed management.

Story Map

The Story Map serves as a companion to the initial draft plan. The Story Map provides some important planning context and case studies of lands where integrated weed management has already been implemented.
View the Story Map

Community Survey

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.
Community Survey Results

Email Updates

Sign up for news alerts to be notified about updates to the management plan.

Parks & Open Space will not be conducting any aerial herbicide applications until the integrated weed management plan has been updated and a decision on whether to resume applications has been made.

Daily Planned Herbicide Applications

Herbicides currently applied to open space areas that are open to the public are reported below.

View Past Activity

Daily Planned Roadside Mowing

Mowing currently being performed along county maintained roads are reported below.

View Past Activity

Additional Information

Please call the weeds hotline at 303-441-3940 for daily updates.

If you have any concerns or would like to learn more about the herbicides being applied, please contact the National Pesticide Information Center.

Management

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

  • 25,000 acres of land designated as natural areas.
  • 7,000 acres of agricultural leased land that serves as wildlife habitat.
  • 685 miles of county maintained road right-of-way.

Aerial Herbicide Applications

Parks & Open Space will not be conducting any aerial herbicide applications until the integrated weed management plan has been updated and a decision on whether to resume applications has been made.

Eradication

The Boulder County Noxious Weed Management Plan requires eradication of all List A species, as mandated by the state, and containment and suppression measures for 13 of the List B species identified as significantly troublesome in Boulder County. Of the 18 List A species, 10 are currently known to exist in Colorado, and nine of those are known to exist in Boulder County.

Staff utilizes an integrated pest management approach to controlling weeds that include mowing, hand pulling, insect bio-control, cultural control (tilling weeds and planting desirable vegetation), and herbicide application. Herbicides are only used in targeted areas.

When controlling noxious weeds on open space properties, staff are careful to use the least damaging and most effective weed control strategies available. Staff always consider the local ecology to maintain and support the rich ecosystems of open space lands.

Goals

  • Minimize the occurrence of weeds and associated negative impacts on native plant communities, agricultural lands, and public corridors.
  • Utilize an integrated weed management approach in order to prevent the introduction of new invasive plant species, eradicate isolated or limited populations, and contain and manage weed species that are well established within the county.
  • Stay current with weed management research and innovative management techniques that may increase effectiveness of weed control and/or decrease environmental impacts.
  • Promote education and awareness of new and potential invasive weed species.

Cheatgrass

Cheatgrass (downy brome) reduces native plant diversity, impacting resources for wildlife including native pollinators and increasing the risk for negative outcomes during wildfires.

On June 22, Scott Nissen, Professor Emeritus at Colorado State University, gave a presentation to the Boulder County Parks & Open Space Advisory Committee on the behavior of cheatgrass and the associated impacts to open space and natural areas.

What You Can Do

  • Identification and do not plant them in your garden. If they already grow in your garden, remove them.
  • Report a Concern on private property.
  • Parks, Environment, Gardening & Agriculture Volunteer Opportunities
  • 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.
  • Attend a Weed Identification and Management Workshop through CSU Extension.

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

On Open Space

If you see noxious weeds on open space, please let us know.

Report Weeds on Open Space

Contact Us