Malheur National Forest to begin invasive plant treatments
By Mindy McKerrall on Thursday, April 23rd, 2026 in Eastern/Southeast Oregon News More Top Stories
HARNEY AND GRANT COUNTY(Released from U.S. Forest Service)-The Malheur National Forest will soon begin invasive plant control on the forest, with work continuing from April through November. We use an integrated approach for invasive weed control, including herbicide application, manual removal, biological control, prevention, and restoration. This project is a continuation of work started under the 2015 decision for the Malheur Site-Specific Invasive Plants Treatment Project.
Invasive species negatively affect biodiversity, wildlife habitat, animal forage, and streamside vegetation. Invasive plants targeted for treatment include knapweeds, non-native thistles, St. Johnswort, houndstongue, sulphur cinquefoil, toadflaxes, whitetop, perennial pepperweed, spurges, and invasive annual grasses. Most herbicide treatments will be spot application to individual invasive plants using backpack or hand sprayers from ATVs or trucks. Some broadcast application is also planned for select roadsides and gravel pits. Herbicides we use include aminopyralid, chlorsulfuron, clopyralid, glyphosate, imazapic, imazapyr, indaziflam, metsulfuron methyl, sethoxydim, sulfometuron methyl, and triclopyr.
Notification signs will be placed for herbicide applications in high-use areas at the time of treatment. A blue marker dye that fades over time will be mixed with herbicides to show where application occurred. We avoid herbicide application in apparent edible and medicinal plant collection areas. Herbicide application in post-fire areas will occur after morel collecting season has ended in late spring. Please contact us with your planned collection areas if you would like for us to avoid them or consider other appropriate invasive control strategies.
The following campgrounds will have no herbicide use in 2026: Head O’Boulder Forest Camp on the Blue Mountain Ranger District, Slide Creek on the Prairie City Ranger District, and Idlewild on the Emigrant Creek Ranger District. We may still apply herbicide to roads and invasive patches nearby but outside of these campgrounds. The remaining campgrounds will have at least half the campground herbicide-free in a 30-day period.
Partners include Grant Soil and Water Conservation District, Harney Soil and Water Conservation District, Harney County Weed Control, Harney Cooperative Weed Management Area, Monument Soil and Water Conservation District, North Fork John Day Watershed Council, Oregon Department of Agriculture, Rocky Mountain Elk Foundation, the National Wild Turkey Federation, private landowners, and permittees. Funding sources include appropriated dollars, post-fire recovery, and Title II projects.
For more information and location maps of herbicide treatments please visit the Malheur National Forests Invasive Species page.
