Noxious Weeds

Noxious weeds are a major concern in the Boise District Office and throughout Idaho. Noxious weeds produce large volumes of seed, spread quickly and overtake desirable native plant communities. They pose a serious threat to the health of wildlife habitats, river systems and recreation areas, as well as to pastures and croplands. At their current rate of spread (estimated at 14 percent per year), noxious weed populations in Idaho are expected to double in less than 6 years

BLM’s Boise District Office (including the Owyhee, Bruneau and Four Rivers Field Offices) is working to identify and reduce weed infestations in southwestern Idaho. For example, in the Bruneau Field Office between 1996 and 2003, approximately 142 acres of weeds were treated primarily using chemical means. Bruneau BLM focuses its attention on tamarisk along river corridors, spotted knapweed in Little Jacks Creek, whitetop in Pixley Basin and along the Mud Flat Road and rush skeletonweed and Russian knapweed near Highway 51. Chemical means are often used to control weeds, but the preferred treatment method of the Boise District is biological control.

Weeds likely to be seen in the Boise District:

Hoary cress	Perennial pepperweed	Puncturevine	Purple Loosestrife
Black henbane	Dalmation toadflax	Spotted knapweed	Diffuse knapweed
Russian knapweed	Rush skeletonweed	Canada thistle	Scotch thistle
Yellow starthistle	Leafy Spurge	Tamarisk	Russian olive

*Bold type signifies invasive weeds and regular type signifies noxious weeds.

How can I control the spread of noxious weeds?

You can help prevent the spread of noxious weeds by taking simple steps while exploring and enjoying public lands. Recreationists and other public land users should be able to identify noxious weeds and take actions to prevent their spread. Boaters should clean boats and trailers, while campers and hikers should check all clothes and camping gear for seeds and clean the undersides of their cars. If a noxious weed is spotted on public lands, it is important to pull the weed up by the roots, dispose of all parts in a plastic bag and report its location and description to the nearest BLM field office or Forest Service. By taking preventative action, the BLM Boise District will be able to maintain healthy rivers and wildlife habitats for years to come.

Cooperative Weed Management

The Owyhee Field Office is part of the Jordan Valley Cooperative Weed Management Area (CWMA). The BLM, working in cooperation with Owyhee County, focuses on treating infestations of tamarisk and whitetop within the Owyhee Field Office, while the CWMA focuses on the leafy spurge infestations.

For the past two years the CWMA has contracted with High Country Sprayers to treat leafy spurge in the Boulder Creek watershed where vehicle access is impossible and access by foot, with a backpack sprayer, is also extremely difficult. In order to effectively treat this area the contractor brought in mules to pack-in herbicide to treat numerous leafy spurge infestations throughout this area.

Over 4.5 million acres of state, private and BLM lands located within portions of Malheur County, Oregon, and the Owyhee Field Office make up the CWMA. The CWMA is comprised of several landowners along with representatives from Oregon and Idaho BLM, Idaho Department of Lands, Owyhee County and Malheur County Weed Departments, Idaho Department of Agriculture, Oregon Department of Transportation, The Nature Conservancy (TNC), and the Owyhee Watershed Council.

The CWMA has brought together everyone with responsibility for weed management within the CWMA, developed common objectives, set realistic priorities, facilitated effective treatment methods, and coordinated efforts along logical geographic boundaries. Through annual weed seminars in Jordan Valley the CWMA has provided numerous educational opportunities about the problems associated with noxious and invasive weeds.