GVM Noxious Weed Program

Some plants are “weedy” but “noxious weeds” are in a special category. Noxious weeds are non-native, invasive and formally designated by Federal, State or County governments. They have the ability to displace native plants and take over forming homogeneous stands across the landscape. It is estimated that there are at least 1.4 million acres in Colorado that are infested.

Leafy Spurge Infestation

GVM has had an Ecology Committee that has worked on noxious weeds since at least 1999. The committee is filled by volunteers and more people are always welcome. No experience needed. The committee provides site assessments, information, small amounts of herbicide and manages noxious weeds in community greenbelts. As funding is available, roads may be included.


Cheatgrass Infestation

The GVM Noxious Weed Committee (NWC) follows the guidelines set out by the State of Colorado and works closely with the Larimer County Weed District (LCWD). The link below will take you to the website that describes the priority system used by the State of Colorado: Colorado Priority System.



Larimer County is our closest partner for local information as well as enforcement. Larimer County has the ability to work with landowners for compliance with local laws. GVM rarely asks for enforcement actions from the county. The link below will take you to the LCWD website that provides information about their mission: Larimer County Weed District Website.

GVM has 18 noxious weed species recorded to date; however, the most common by far are Canada thistle, musk thistle, diffuse knapweed, Common mullein and cheatgrass. Select this link to view the full list of known species in GVM:  GVM Weeds.

Weed Management

In addition to the above 5 species, the NWC keeps an eye out for less common noxious weeds that show up. The intent is to detect them early and respond as rapidly as possible before they spread. The primary way the NWC responds is to contact landowners with a courtesy letter when less common weeds are detected. These are often along CR74E and include sulfur cinquefoil, dalmation toadflax, leafy spurge, and houndstongue.

There are many ways to manage weeds, some more effective than others depending on the species and the extent of the problem. Some weeds such as musk thistle and mullein have weak roots which means they can be readily pulled or dug without the need for herbicide. Cheatgrass can also be pulled but only on small patches.

For information about managing the 5 primary noxious weeds here in GVM, see fact sheets and brochures on the Resources page of this website Ecology Team Resources Page.

For more information about the 5 primary noxious weeds here in GVM, click on the arrows under this Weed page.

We also have a short manual for further reading Treatment Manual.