Noxious weeds a threat to Colorado’s native plants and crops September 19, 2024 Home Explore The Naturalist's Journal Noxious weeds a threat to Colorado’s native plants and crops Share FacebookTwitterEmail A serious and growing problem in the West is the invasion of non-native plant species, commonly called noxious weeds. Noxious refers to the species’ aggressive behavior, which damages native Colorado plant communities or economic crops. They do not have predators so they can adapt very successfully to Colorado’s environment, giving them an advantage over native species. Noxious weeds outcompete native plants for food, space, light and nutrients.