The Larimer County Weed District offers the following services to help you achieve the most cost-effective solutions to your land management issues. Please contact the Weed District at (970) 498-5768 to make an appointment, or if you have any questions.

The Colorado State University/Larimer County Agriculture Extension agent organizes several meetings every year that address weed identification and management, and small acreage pasture management. The times and locations are posted through the Larimer County Agriculture Extension Service, information can also be obtained by calling the Extension office at (970) 498-6003.

Staff from the Larimer County Weed District, are available to give on-site presentations on noxious weed identification and management to HOA's, schools, agencies, or any other interested groups or organizations. Presentations can be by Power Point slide shows or an outside venue in the field identifying plants and giving best management recommendations.

The Larimer County Weed District and Colorado State University Weed Science Department are working cooperatively to establish weed management study areas around the county. Sites have been established to investigate chemical control treatments for cheatgrass, volunteer rye, leafy spurge, Canada thistle, Russian knapweed, tamarisk, and Russian olive. Additionally, an insect bio-control study on Dalmatian toadflax has been established.

Tours of the demonstration sites are available to interested groups. Attendees have the opportunity to see weed management results from standard herbicide treatments as well as soon-to-be-labeled products. Study sites are located on range and pasture locations, so impact on grasses and other desirable species as well as weed control can be assessed. Information derived from the trials can be obtained through the Larimer County Weed District. Such information is used to help establish recommendations for best management practices.


The Larimer County Weed District has selective herbicides available for purchase with no additional paperwork required. The Weed District is committed to offering herbicides that are proven to be the most effective with the least environmental impact.

Learn more about the cost share program.

Site VisitWe offer free site visits to all landowners in Larimer County. During a site visit a weed specialist will:

  • Walk the property with you
  • Identify plants
  • Understand your goals for the land
  • Consider any sensitivity you may have
  • Discuss best management practices with alternative solutions when applicable

Based on the above factors the weed specialist will:

  • Make a quality, cost effective recommendation
  • Ensure that you understand what needs to be done and the timing of various controls
  • Offer estimates on what it may cost to accomplish your goals

Call us to set up an appointment at (970) 498-5768 and we will coordinate a date and time that will work best for you and the specialist.


The weed management of county maintained rights-of-way is the responsibility of the Larimer County and mandated by the Colorado Noxious Weed Act. Property owners requesting no spray are responsible for noxious weed management within that zone. Failure to comply will result in Larimer County resuming spraying operations. The posting requirements listed below must be met if the County is to honor a request to refrain from treating an area with herbicides.

  • Signs must be posted immediately adjacent to the rights-of-way but not on the rights-of-way.
  • Signs must be posted at each end of the property; spraying operations will end at the point where the first sign is posted and begin at the point where the second sign is posted.
  • Signs must be clearly visible to approaching traffic from the road; they must be at least 36 inches above the ground and not obstructed from view.
  • Signs and the lettering on them must be large enough to be easily read from 20 yards distance.
  • Requests need to be submitted annually.

To request County Road No Spray areas, please call us at (970) 498-5768, or submit your request using the link below. You will need to create an account in the online portal first before submitting your request.

Submit a Do Not Spray Request

Additional Resources

Larimer County Weed District

OFFICE: 2649 E. Mulberry St., Suite 6, Fort Collins, CO 80524
PHONE: (970) 498-5768
OFFICE HOURS: 8 a.m. - 4 p.m., Monday - Friday (except holidays) Please call ahead for an appointment.