Herbicide treatment planned near Metolius River

The Deschutes National Forest will apply herbicides to invasive plants in an area adjacent to the Metolius River and the Metolius River Trail during the first week in October.

From Oct. 1-4, the Sisters Ranger District will use two herbicides (Roundup Custom® and Polaris®) to treat invasive non-native ribbongrass , reed canarygrass and yellow flag iris on approximately two acres near the Metolius River. Treatments will take place in select locations from just upstream of the confluence with South Fork Lake Creek downstream to Candle Creek Campground.

The method of treatment will be spot applications with a backpack or hand-sprayer. It involves application of herbicide to foliage of target invasive plants to minimize effects to native plants. The applied herbicides will dry within an hour of being applied and do not pose a risk to human or animal health under the concentrations being applied, officials said.

The Metolius River Trail will remain open during treatment, but official said the public should remain on the trail during active treatment operations and keep dogs leashed. Blue dye is added to the herbicides to make treatment areas clearly visible.

Ribbongrass , reed canarygrass and yellow flag iris are invasive plants overtaking native sedges, wildflowers, and shrubs within the river’s riparian habitats. These non-native species out-compete most native species and present a major challenge in protecting the ecosystem of the Metolius River.

Restoring and protecting the Metolius Wild and Scenic River and its values including fish, wildlife, water quality, ecology, scenery, and cultural values is a priority of the Deschutes National Forest.

The two herbicides being used were approved through an environmental analysis in 2005 and a supplemental environmental analysis in 2012.

For more information, please contact Beth Johnson, Sisters District Botanist at 541-549-7727.