Identify This Weed – send us your photo of a weed to identify.
The Larimer County weed management program will strive to minimize the occurrence of weeds and associated negative impacts on native plant communities, agricultural lands and public corridors in Larimer County. In doing so, staff will strive to establish and maintain relationships within the community based on best land stewardship practices. We will achieve this through collaborative research and discourse, making ourselves and our resources accessible to the public and continuing education amongst the general public as well as land stewardship professionals.
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 State 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 Mountain Region. 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, disease and other limiting factors that kept the species in check in its native land.
The Colorado State Noxious Weed Act lists 71 weed species considered to be a threat to the economy and environment of Colorado. Another 24 species are listed on the state's Watch List. The lists are categorized by priorities:
The Larimer County Noxious Weed Management Plan requires eradication of all List A species, as mandated by the state, and containment and suppression measures for 16 of the List B species identified as significantly troublesome in Larimer County. County outreach programs emphasize identification and management of the 16 List B species but the Weed District reserves the right to enforce on any state-listed noxious weed if infestation size and density deems it necessary. Other species, too common to require control, are still considered troublesome weeds in the County and the Weed District will provide best management practices. The Weed District has also compiled a list of native and non-native plants that are often a concern with Larimer County residents that can be found in Frequently Asked About Pasture Plants. For a comprehensive listing of weeds and to see a summary of the weed law go to Weed Law Summary and Weed Lists.