The Larimer County Weed District office has moved

Visit us at our new address at The Ranch complex in Loveland. 
OFFICE (as of Dec 1, 2023): 
5450 Arena Circle, Suite 110, Loveland, CO 80538    MAP
MAILING ADDRESS: 5280 Arena Circle, Loveland, CO 80538
PHONE: (970) 498-5768

OFFICE HOURS: Please call ahead for an appointment. Wednesday - Friday (except holidays)  8:30 a.m. - 4 p.m.

The Larimer County weed management program strives to minimize the occurrence of weeds and associated negative impacts on native plant communities, agricultural lands and public corridors in Larimer County.


  • Assist landowners with noxious weed problems through plant identification, weed management recommendations and development of vegetation management plans
  • Promote noxious weed education and awareness through community presentations, printed materials and site visits
  • Manage noxious weeds on Larimer County property and roadside rights-of-way
  • Enforce the Colorado Noxious Weed Act on non-compliant property owners

Cameron Peak Fire Recovery  

New Cost-Share Program

Let us share the cost of weed control with you through our cost-share program. If you live within the Weed District boundary you can receive reimbursements for spraying and mowing up to $1,000.

Weed district boundary map inside larimer county

A weed is often defined as "a plant out of place". This simple definition can refer to many different plants in many settings. A "noxious weed" has a special definition with a legal connotation. The Larimer County Weed District follows the guidelines of the Colorado Noxious Weed Act, which defines "noxious weeds" as plants that are exotic and invasive. Exotic means non-native, or weed species that originated in other parts of the world. Most of the weed species considered noxious in Colorado originated in regions of Europe and Asia with a climate similar to the Rocky Mountains.

Invasive plants are those vigorous enough and competitive enough to crowd out desirable plants and, in doing so, decrease native plant diversity and wildlife habitat. The increased vigor and competitive ability of a non-native plant is the result of being introduced into a country with different grazing animals, predatory insects and diseases and without the limiting factors that kept the species in check in its native land.

The Colorado Noxious Weed Act lists weed species considered to be a threat to the economy and environment of Colorado. The lists are categorized by priorities:

  • List A species are of the highest priority. These weeds are not well established in Colorado, are potentially a large problem to this state and require mandatory eradication by local governing agencies.
  • List B species are common enough in parts of the state that eradication is not feasible, though the species are still recommended for eradication, suppression or containment depending on distribution and densities around the state.
  • List C species are widespread and well established.

The Larimer County Noxious Weed Management Plan requires eradication of all List A species and eradication or suppression of List B species depending on abundance within the county. Learn more about the Colorado Noxious Weed Act and weed lists.

The Larimer County Weed District encompasses the eastern 1/6 of the county. Funding for the Weed District is provided by a 0.143 mill levy paid by residents within the Weed District boundary. Activities conducted outside the Weed District are supported through an enterprise program that obtains funds from contracted weed management work with private landowners; federal, state and local agencies; and state and federal grants.


Weed District History

A group of farm leaders under the direction of the Extension Director initially laid the groundwork for the formation of the Larimer County Weed Control District in 1959.

The Fort Collins Weed District was formed on March 2, 1960. The Loveland Weed Control District was formed about a month later on April 13.

The two districts were formed as part of a pilot program, which was to last three years, to control Canada thistle. Landowners outside the pilot districts saw just how successful the program was in combating Canada thistle, and they petitioned to form another district, which would include more land in Larimer County.

At first, some committee members wanted to include the rest of Larimer County in its entirety. This was voted down because of the vast areas of range and forest lands. The final decision was to include Canada thistle control on all irrigated lands within the Northern Colorado Water Conservancy District. Thus, the East Larimer County Weed Control District was formed on April 19, 1962.

In addition, the two pilot districts petitioned for an extension of their termination date in November 1962. A new termination date was set for December 31, 1966.

In February 1967, the Advisory Committee members of the three districts petitioned to dissolve the districts and consolidate them into one. On March 1, 1967, the three districts became the Larimer County Weed Control District.

The original districts were formed using the parameters of The Pest Act, Ch. 6, Art.16, CRS 1953. The Larimer County Weed Control District now operates under 35-5 CRS 1973 and 35-5.5 CRS 1990.

The districts were originally funded out of the Larimer County general fund. In 1982, the Larimer County attorney began to look at the option of a special mill levy to fund the Weed District. Today, the Weed Control District is funded by a mill levy assessed on landowners within the Weed District boundaries. According to 35-5 CRS 1973, the mill levy cannot exceed 2 mills. The Weed District now operates on a budget funded by a mill levy of .143 mills.

The Larimer County Land Stewardship Advisory Board consists of seven members appointed by the Larimer County Board of County Commissioners. The purpose of this group is to serve as a sounding board for overall weed control policy and forestry issues and to represent county constituents on issues for the Larimer County Board of County Commissioners.

The weed management of county-maintained rights-of-way is the responsibility of the Larimer County Weed District 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 Larimer 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, 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

If you do not have Internet access, please call (970) 498-5768 for assistance

Larimer County Weed District

OFFICE (as of Dec 1, 2023): 5450 Arena Circle, Suite 110, Loveland, CO 80538
MAILING ADDRESS: 5280 Arena Circle, Loveland, CO 80538
PHONE: (970) 498-5768
OFFICE HOURS: Please call ahead for an appointment. Wednesday - Friday (except holidays), 8:30 a.m. - 4 p.m.