Exotic and Invasive Rangeland weeds

Authors: Clements, Darin; Harmon, Daniel

Submitted to: Popular Publication
Publication Type: Popular Publication
Publication Acceptance Date: 12/11/2025
Publication Date: 1/5/2026
Citation: Clements, D.D., Harmon, D.N. 2026. Exotic and Invasive Rangeland weeds. Progressive Rancher. 26(1):27-30.

Interpretive Summary:

Technical Abstract: Exotic and invasive weeds play a critical role on rangelands throughout the Intermountain west. A weed is simply a plant growing in a site where it is not desired. You can make up your own standards for what constitutes desirability. It may be forage production, nutritional quality, or season of growth or have little to do with forage characteristics. Watershed protection, chance of ignition and rate of spread of wildfires, and wildlife habitat are all plant characteristics that influence individual perception of plant desirability. A weed may be a desirable plant in one location and a weed in another. For example, in the salt deserts of Nevada, desert salt grass is a desirable forage species in alkaline/saline habitats surrounding playas. It is virtually the only herbaceous forage species adapted to grow in such environments. In the irrigated alfalfa fields of Nevada, it is considered a serious herbaceous weed. Numerous weed species cause significant environmental damage resulting in significant rangeland degradation. The exotic and invasive annual grass, cheatgrass, for example, increases the chance, rate, spread and season of wildfire and with each wildfire season more and more critical grazing and wildlife resources are burned and converted to annual grass dominance. Effective and efficient weed control efforts to control the numerous weeds found throughout western rangelands are daunting. It is not uncommon to experience a level of control for one weed species, only to have another exotic and invasive weed become the new problem. Even in sites where we good near control of the exotic and invasive cheatgrass, we experience increases in mustards and thistles when seeding of desirable perennial grasses fail. Also, these weedy species also have the ability to invade areas with excellent perennial species on site under certain favorable conditions. The acknowledgment of the numerous weed species on rangelands and the ecology of these weed species will be critical in reducing further advancement of weedy species and reducing the level of rangeland degradation.