The Montana Department of Agriculture (MDA) has confirmed the presence of rush skeletonweed at several new sites in western Montana. This invasive plant, scientifically known as Chondrilla juncea, was recently found outside its usual range in the state. Notable locations include two plants in the I-90 median west of Three Forks, a few plants south of Dillon on I-15, and individual plants near recent forest fire sites close to Wise River and Wisdom.
Rush skeletonweed is classified as a Priority 1B Noxious Weed in Montana, necessitating eradication or containment efforts along with educational initiatives. In response to these discoveries, MDA staff collaborated with county weed districts and the Montana Department of Transportation to survey extensive roadside areas for additional occurrences. Any detected plants were mapped, clipped of flowering parts for incineration, and treated with herbicide. Ongoing follow-up measures are planned.
While already present in western Montana, rush skeletonweed is spreading along I-90 in Missoula and Mineral counties. Significant infestations have been identified and addressed this summer in Ravalli, Missoula, Flathead, and Lincoln counties. The plant primarily affects rangeland, open forests, and natural areas but has not yet been found in small grain fields within the state. However, it poses a significant threat to agriculture; for instance, it has reduced crop yields by up to 70% in Australia due to competition for resources like nitrogen and water.
The optimal time for spotting rush skeletonweed is from September through October when it flowers and produces seeds. Those who suspect they have found the plant are encouraged to report sightings via EDDMapS or by submitting photographs and GPS coordinates to local authorities including county weed coordinators or Montana State University Extension agents.
For more information on identifying rush skeletonweed or reporting sightings, visit the MDA’s Early Detection Rapid Response webpage at agr.mt.gov/Noxious-Weeds.
Information from this article can be found here.
