Noxious weeds are plants that are not native to the county. Most have come from Europe or Asia either accidentally or as ornamentals that have escaped. These plants have an advantage because the insects, diseases, and animals that would normally control them are not found here. Because these plants have developed specialized mechanisms to survive, they are able to spread at an alarming rate.
Due to COVID-19, the Community Planning & Permitting Department is providing most services virtually. Our physical office in Boulder is currently closed, but staff is available for virtual appointments. Schedule an appointment.
Identification of Noxious Weeds
List A weeds are rare weed species that are subject to eradication wherever detected in order to protect neighboring lands and the state as a whole.
Less Than 10 Known Species in Boulder County
More Than 10 Known Populations in Boulder County
Not Known in Boulder County
List B Species Designated by the Board of County Commissioners for Required Management & Control
Other List B Species
Management is recommended, but not required, for List C Species.
Watch List Species that have been determined to pose a potential threat to the agricultural productivity and environmental values of the lands of the state. The Watch List is intended to serve advisory and educational purposes only. Its purpose is to encourage the identification and reporting of these species in order to facilitate the collection of information to assist in determining which species should be designated as noxious weeds.