Noxious Weeds

Announcing the Prettiest Noxious Weed in El Paso County as Myrtle Spurge.The votes are in and our “Prettiest” #NoxiousWeed in El Paso County is… Pretty? Yes! Non-Native? Yes! #Invasive? Yes! Harmful or #poisonous? Yes! Grow it on purpose? NO! Hello MYRTLE SPURGE! Thanks for voting!

Noxious weeds are plants (or parts of a plant) that have been “designated by an agricultural or other governing authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or livestock.”¹ These plants are non-native to the region, aggressive and invade native plant communities or cash crops, poisonous, and/or host detrimental insects, diseases, or parasites.

Getting rid of noxious weeds is not an easy task and takes everyone’s participation to meet this goal.2 —Elaine Freeth

The Colorado Department of Agriculture prioritizes these plants within the following groups. Information for identification and biological, chemical, and mechanical control methods are available with links to each of the following images.

List A: These are to be eradicated

List B: Stop the continued spread of these species
List C: Provide education, research, and biological control resources to local governing groups
Watch List: Serves an advisory and educational purpose to encourage identification and reporting

Who Can Help?

Colorado Department of Agriculture
The aim of the Noxious Weed Program is to control noxious weeds, the non-native aggressive invaders that replace native vegetation, reduce agricultural productivity, cause wind and water erosion and pose an increased threat to communities from wildfire. We do this by preventing the introduction of new invasive species; eradicating species with isolated or limited populations and containing and managing those invasive species that are well-established and widespread.

To accomplish these goals the program coordinates the efforts of local, state and federal noxious weed managers; provides funding for local entities to carry out on-the-ground weed management projects; conducts education and outreach activities and supports similar local activities; and maintains close contact with neighboring states and counties to prevent the interstate spread of noxious weeds.

Palisade Insectary
Biological control is a sustainable approach to pest management that utilizes the natural enemies of noxious weeds or pests. The Palisade Insectary imports, rears, researches, and distributes biological control agents for the state of Colorado. Successful biological pest control reduces production costs, decreases the amount of chemicals entering the environment, and establishes colonies of beneficial insects offering a natural permanent pest control solution. More than 90 species have been cultured, studied and released for biological control since the Insectary was founded in 1945.

El Paso County Community Services Department
The El Paso County Community Services Department, Environmental Division, Noxious Weed Section monitors both public and private control of noxious weeds as required by the Colorado Noxious Weed Act. The Division uses integrated weed management techniques including mechanical (mowing, pulling). chemical (herbicide treatments), biological (insects), and cultural (re-seeding with native plants).

1. Wikipedia contributors. “Noxious weed.” Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 12 March 2022.

2. Freeth, Elaine. Noxious Weed Removal Is a Team Effort | Ranger Ramblings, 23 June 2021,