Idaho
Noxious Weeds 
Acres of Noxious Weeds on BLM-Managed Lands in Idaho
Noxious weeds are undesirable and potentially harmful plants that are spreading at an alarming rate across the western United States. Most noxious weeds are "exotic" plants that are native to Europe and Asia. They became established in the United States as settlement and commerce expanded in the mid-1800s. Noxious weeds are able to spread widely because they have few obstacles in the form of native insects or diseases to control their growth, and because they can out-compete native plants in many areas. Weeds can also invade and area following wildland fire.
Noxious weeds are becoming a severe threat to biological systems in the West. About 8.5 million acres of the 180 million acres of BLM-managed land are seriously infested with noxious weeds, according to a 1996 inventory. Noxious weeds can decimate the land's potential and impact many sectors of our economy, destroying wildlife habitat and lowering forage use, and adversely affecting hunting, fishing, livestock grazing, crop production, and other recreational and commercial uses.
Although the weed problem is already significant, it has the potential to become much worse. Noxious weeds are estimated to be spreading at the rate of about 2,300 acres per day on Western federal lands alone. The challenge is to contain existing weed infestations and to prevent weeds from spreading to unaffected areas. BLM is working in cooperation with federal and state agencies, county governments, and private landowners to identify and control these invasive plants before they degrade ecosystems and damage land productivity.
In Idaho, the BLM is working closely with the Idaho Department of Agriculture (IDA) and county governments to combat noxious weeds. The BLM participates with state and local governments in establishing Cooperative Weed Management Areas, which can utilize local, state and federal resources to inventory and treat weed infestations on public and private lands. Idaho's American Indian Tribes also support and participate in these and other efforts. Beginning in 2009, the BLM will use funding from the American Recovery and Reinvestment Act (ARRA) to eradicate noxious weeds across the state, in partnership with state and county governments, weed districts, universities, and Tribes.
Through the Great Basin Initiative, the BLM is working to prevent the spread of noxious weeds in Nevada, western Utah, southern Idaho, southeast Oregon, and eastern California.
The BLM is also helping fund a statewide database of noxious weed locations. The database is an important step in developing a cohesive strategy for reducing the noxious weeds in Idaho.
Acres of Noxious Weeds on BLM-Managed
Lands in Idaho
| Species | Infested Acres Inventoried | Infested Acres Estimated |
| Acroptilon repens (Russian knapweed) | 8,367 | 13,764 |
| Cardaria draba (White top) | 1,986 | 4,335 |
| Carduus nutans (Musk thistle) | 11,367 | 19,545 |
| Centaurea diffusa (Diffuse knapweed) | 24,444 | 91,378 |
| Centaurea maculosa (Spotted knapweed) | 20,680 | 43,600 |
| Centaurea solstitialis (Yellow starthistle) | 5,102 | 7,102 |
| Chondrilla juncea (Rush skeletonweed) | 22,315 | 85,330 |
| Chrysanthemum leucanthemum (Oxeye daisy) | 100 | 4,300 |
| Cirsium arvense (Canada thistle) | 22,402 | 37,682 |
| Cirsium vulgare (Bull thistle) | 315 | 1,400 |
| Convolvulus arvensis (Field bindweed) | 10 | 300 |
| Crupina vulgaris (Common crupina) | 60 | 200 |
| Cynoglossum officinale (Hounds tongue) | 100 | 400 |
| Cytisus scoparius (Scotch broom) | 4 | 300 |
| Euphorbia esula (Leafy spurge) | 59,431 | 74,489 |
| Hieracium aurantium (Orange hawkweed) | 20 | 900 |
| Hieracium pratense (Yellow hawkweed) | 300 | 2,800 |
| Hypericum perforatum (St. Johnswort) | 900 | 3,800 |
| Hyoscyamus niger (Black henbane) | 1,626 | 1,573 |
| Linaria genistifolia (Dalmation toadflax) | 421 | 2,136 |
| Linaria vulgaris (Yellow toadflax) | 346 | 104 |
| Potentilla recta (Suphur cinquefoil) | 400 | 4,600 |
| Tanacetum vulgare (Common tansy) | 65 | 900 |
| Onopordum acanthuim (Scotch thistle) | 1,330 | 3,000 |
| Lythrun salicaria (Purple loosestrife) | 205 | 152 |
| Tamarix ramosissima (Salt cedar) | 3 | 49 |
| Taeniatherum capt-medusae ( Medusa head) | 701 | 14,167 |
| Conium maculatum (Poison hemlock) | 246 | 1,754 |
| Isatis tinctoria (Dyer's woad) | 990 | 1,177 |
| Aegilops cylindrica (Jointed goatgrass) | 220 | 21 |
| Lepidium latifolium (Perennial pepperweed) | 200 | 300 |
| Tribulus terrestris (Puncture vine) | 30 | 0 |
| TOTAL | 189,932 | 421,558 |
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