Protecting the Upper Ruby River from Invasive Plants

Gravelly range  looking toward the Ruby River.

Gravelly range looking toward the Ruby River.

The Ruby River in southwestern Montana is nestled between the Snowcrest and Gravelly Mountain Ranges of Madison County. The river flows northward about 76 miles, sculpting a wide valley before joining the Beaverhead River. Ranching, farming and recreation in the Ruby Valley are cornerstones of the economy of Madison County. With over 2.3 million acres of land and less than 7,600 residents in the county, protecting natural resources from invasive plants is vital to preserving the rural lifestyle and ranching heritage of Ruby Valley landowners.

No one understands that better than Rick Sandru, a third-generation Montana rancher and president of the Ruby Valley Stock Association. “Noxious weeds are a growing problem that threaten private and public land in the upper Ruby Valley,” explains Sandru. “I watched weeds spread in parts of western Montana, so when we saw them establishing on our summer grazing allotment we knew something had to be done. In 2011 we were trailing cattle to summer pasture and decided that a planned, organized weed control effort was needed, and it needed to happen soon!”

Making It Happen

Sandru and seven other ranching families that compose the Three Forks Grazing Association and their herd riders surveyed and recorded weed infestations within their grazing allotment (see Map). Results of the survey showed that houndstongue, spotted knapweed and field scabious were the most widespread species (Table 1). A total of about 830 acres of noxious weeds are scattered over the 65,000-acre area. Although some weed infestations are difficult to access, many of the weeds are associated with roads, trails and other disturbed sites.

Once the initial survey work was completed, Sandru contacted the Ruby Watershed Council, Ruby Valley Conservation District, Ruby Grazing Association and Madison County Weed District. Together they formalized the Upper Ruby Watershed Cooperative Weed Management Area (CWMA). The group developed a comprehensive plan that focused on: 

  • Improving the effectiveness of prevention and control efforts on invasive plants within the CWMA.

  • More efficiently utilizing resources across political boundaries through coordination and strategic planning.

The partnership has expand since 2011 to include 16 different agencies, groups, and businesses (Table 2). 

Map showing infestations of noxious weeds in the Upper Ruby Watershed Cooperative Weed Management Area.

Table 2. Partners in the Upper Ruby Valley CWMA

TABLE 1. Weed species and acreage infested within the 65,000-acre cooperative weed management area. Weed inventories are still needed on the eastern allotments within the project area.

Management Goal=Healthy Lands

Invasive plant management within the CWMA has concentrated on improving and protecting desirable vegetation, reducing soil disturbance, monitoring, and herbicide treatments. Although weeds are scattered over a large landscape, infestations are at a level that can still be contained and controlled.

The first cooperative noxious weed spray day was organized by Sandru and Madison County Weed District in Fall 2011, and these events have continued annually since that date. “Herbicide treatments have been effective at reducing the size and distribution of invasive plants within the project area,” explains Margie Edsall, Madison County Weed Coordinator. “We apply Milestone® at 7 fluid ounces per acre (fl oz/A) to control spotted knapweed, field scabious and Canada thistle, and we are getting more than 90 percent control a year later. On sites where we have houndstongue or hoary alyssum intermingled with knapweed or thistle we add Escort at 1 ounce per acre (oz/A) to Milestone at 7 fl oz/A, and control has been excellent.” Monitoring for satellite infestation continues to be an important part of the effort to find and possibly eradicate new infestations.

“Maintaining grass on our summer grazing allotment is a matter of survival for ranchers in the Upper Ruby Valley,” explains Sandru. “But managing weeds also has other benefits including protecting wildlife habitat, reducing soil erosion, improving water quality, and enhancing natural resource values that are critical in the Ruby River watershed.”

The ranchers that compose the Three Forks and Warm Springs Creek Grazing Allotments recognize that a healthy plant community is critical to protecting natural resource values and minimizing the establishment and spread of invasive plants. Their projects include: 

  1. A successful rest-rotation grazing system that fosters a desirable plant community.

  2. A water system to disperse cattle away from creeks to improve riparian function, stream bank stabilization, and increased aspen regeneration.

  3. Hardened stream crossings and corral relocation.

All of these projects help maximize desirable vegetation and minimize soil disturbance. The result is less sediment moving into the Ruby River, and reduced weed establishment and spread.

In addition to controlling weeds, another testament to the ranchers’ hard work is the successful reintroduction of the Arctic grayling (Thymallus arcticus) to the Ruby River. Sandru explains, “Several years ago we voluntarily agreed to embrace Fish, Wildlife and Parks reintroduction of Arctic grayling to the Ruby River. Grayling need extremely cold and clean water to survive, and this is the only successful reintroduction in Montana. We believe that desirable habitat for the fish is a direct result of our progressive management practices.”


A diverse group of supporters help fund weed management efforts within the CWMA including the Rocky Mountain Elk Foundation, Montana Noxious Weed Trust Fund, and the Resource Advisory Council. Combined, these three groups have contributed more than $40,500 since 2011. The majority of these funds (about $35,000) have been spent on public lands for inventory and control of invasive plants. The CWMA submitted a new grant request to the National Public Lands Council for $150,000 to provide long-term support to the effort.


The future goal of the project is to expand from the Upper Ruby Watershed downstream to the Ruby Reservoir, increasing the CWMA to include more than 135,000 acres. “Even with the success we are having with our current efforts, larger areas still need management,” says Edsall. “The cooperation we have from land owners and agencies is the most effective and efficient way to control invasive plants and prevent their introduction.”

Partners believe that the survival of family ranches and preservation of vast undeveloped landscapes is dependent on long-term management of invasive plants to maintain healthy lands. 

Volunteers. More than 15 ranchers, volunteer commercial applicators and partner agencies dedicate time and resources to controlling weeds in the Upper Ruby Watershed Cooperative Weed Management Area.

RANCHERS MEET in the grazing allotment to discuss weed infestations that need to be treated.

RICK SANDRU and seven other ranching families that compose the Three Forks Grazing Association initiated the Upper Ruby Cooperative Weed Management Area.




Arctic grayling (Thymallus arcticus) are a unique fish species because remnant populations were native to only two of the lower 48 states, Michigan and Montana. Grayling were apparently isolated in both of these areas by the last period of glaciers, which ended 10,000 to 12,000 years ago. Michigan’s grayling were extinct by 1936, but Montana populations continue to persist in a fraction of their historic range. The only remaining native stream-dwelling grayling population in the lower 48 states was found in the Big Hole River in southwest Montana prior to reintroduction to the Ruby River. Fluvial Arctic grayling in Montana are designated as a “Species of Concern” by the Montana Natural Heritage Program, a “Species of Special Concern” by the Montana Chapter of the American Fisheries Society, and a fish of “Special Concern” by the Endangered Species Committee of the American Fisheries Society.


Occurrence of field scabious in the United States and Canada. USDA Plants Database 2014 (

Field scabious (Knautia arvensis) is a tall, tap-rooted perennial plant in the teasel family (Dipsacaceae). This native of Europe has naturalized in areas of southwestern Montana, other northern-tier states in the U.S. and in southern Canadian provinces. Plants are up to 4 feet in height with violet-blue to purple flowers on the ends of long, leafless stalks. One plant can produce up to 2,000 seeds, which may remain viable in the soil for many years. Plants establish easily along roadsides, pastures, meadows, rangeland and disturbed sites. Field scabious spreads rapidly and competes with desirable grasses causing declines in hay production and forage for livestock and wildlife. 

®Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow. Milestone is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Label precautions apply to forage treated with Milestone and to manure from animals that have consumed treated forage within the last three days. Consult the label for full details. Always read and follow label instructions.