Malheur National Forest to begin Invasive Plant Treatments

JOHN DAY, PRAIRIE CITY AND HINES(Released from the 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, and spurges. 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.  

Treatment sites are located across the Malheur National Forest, though this summer we will focus more heavily on areas burned during 2024 wildfires. We will place notification signs 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 typically 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 2025: Dixie on the Blue Mountain Ranger District, Strawberry on the Prairie City Ranger District, and Falls 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. 

A map of this year’s treatment are is located at: https://www.fs.usda.gov/detail/malheur/landmanagement/?cid=FSEPRD498230

Partners include Grant Soil and Water Conservation District, Harney Soil and Water Conservation District, Harney County Weed Control, Harney Cooperative Weed Management Area, Burns Paiute Tribe, Monument Soil and Water Conservation District, North Fork John Day Watershed Council, Oregon Department of Agriculture, Rocky Mountain Elk Foundation, private landowners, and permittees. Funding sources include appropriated dollars, post-fire recovery, and Title II projects. 

For more specific information on timing and location of herbicide treatments, please contact the forest’s invasive plants specialist Jessi Brunson at 541-575-3067 or by email at jessica.brunson@usda.gov

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