Larimer County, CO Landscaping Rules: Weed Ordinances (2026)
Key Facts
- Governing law
- Colorado Noxious Weed Act
- Landowner duty
- Manage noxious weeds (§ 35-5.5-104)
- List A weeds
- Mandatory eradication
- List B weeds
- Containment or eradication
- Enforcer
- Larimer County Weed District
Summary
Colorado's Noxious Weed Act makes every landowner responsible for managing noxious weeds that could damage neighboring land. Larimer County's Weed District enforces this and requires eradication of List A weeds and containment of designated List B species.
It is the duty of all persons to use integrated methods to manage noxious weeds if the same are likely to be materially damaging to the land of neighboring landowners.
Official source re-checked September 7, 2026: the cited page had not changed since it was quoted.
Full Breakdown
Under C.R.S. § 35-5.5-104, all persons must use integrated methods to manage noxious weeds likely to materially damage neighbors' land. Larimer County Weed Control administers the Act on unincorporated land, mapping and requiring treatment of state List A (mandatory eradication) and List B (containment/eradication) species such as leafy spurge, myrtle spurge, and Russian knapweed. This is separate from ordinary lawn-height nuisance rules, which cities set. The county can inspect, notify, and, if an owner fails to act, treat the property and bill the cost.
Violations & Fines
If a landowner ignores a notice, the county (or city) may enter, manage the weeds, and assess the cost as a lien against the property under C.R.S. § 35-5.5-109.
Frequently Asked Questions
Are weeds my legal responsibility in Colorado?
What happens if I do not control them?
Sources & Official References
Other rules in Larimer County
How Larimer County compares: Cities with the Strictest Weed and Property Maintenance Rules·Compare Larimer County to another location·View the Colorado landscaping rules overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.