A weed, simply defined is a plant out of place. Weeds interfere with beneficial uses of the land and water, displace native plants, and affect human and animal health. Weeds of special concern are those which are not native to the area. These have been introduced into areas where there are no natural, ecological controls such as insects or disease which limit their spread. These non-native, invasive weeds pose a significant threat to natural ecosystems on the Boise and Sawtooth National Forests.
Noxious weeds are difficult to control and cause extraordinary negative and ecological impacts.
Over 8 million acres of land in Idaho are severely infested with one of Idaho's 35 designated noxious weeds. Non-native invasive weeds are spreading at a rate of 8 to 12 percent a year on National Forest System lands in the western United States. In 1999, the Boise and Sawtooth National Forests estimated that noxious weeds covered approximately 99,000 acres of the National Forest System lands.