Yellow toadflax may also be referred to as common toadflax or “butter and eggs.” It was introduced from Europe as an ornamental and has now become a serious problem to rangelands and mountain meadows. It is a perennial plant that reproduces from seed, as well as from an underground rootstalk. The flowers are bright yellow with deep orange centers that resemble the snapdragon. Yellow toadflax does well in all types of soils. Its displacement of desirable grasses not only reduces ecological diversity, but also reduces rangeland value and can lead to erosion problems.
Because of its early vigorous growth, extensive underground root system and effective seed dispersal methods, yellow toadflax is difficult to control. Yellow toadflax infests thousands of acres in the Flat Tops wilderness. Populations are also increasing in the Lookout Mountain area above Glenwood Springs and in locations close to the rodeo grounds in Carbondale.