Colorado rubberweed belongs to the sunflower family. It has golden-yellow or orange flowers that resemble asters. Where and When It Grows Colorado rubberweed is a perennial that grows in arid sites at elevations of 6000 to 8000 feet. It is found mostly on mountains and foothills and grows from early spring until the first frost. It is considered an invader plant and may replace more palatable forage plants that have been overgrazed.
Most poisoning occurs in spring or fall.
The plant seems to act primarily as a depressant of the digestive tract. In most cases, the first sign of poisoning to be observed is a green froth around the mouth and nose. Heavy losses during trailing may be prevented by avoiding heavily infested areas. Keep hungry animals away from Colorado rubberweed ranges at all times. If sheep losses become excessive, it may be advisable to change from sheep to cattle on certain ranges.