State Distribution (16 / 50 states)
Alabama Alaska Arizona Arkansas California Colorado Connecticut Delaware Florida Georgia Hawaii Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Ohio Oklahoma Oregon Pennsylvania Rhode Island South Carolina South Dakota Tennessee Texas Utah Vermont Virginia Washington West Virginia Wisconsin Wyoming
Listings by State
| State |
Classification |
Common Name Listed |
Notes |
| Idaho | Class B | Spotted knapweed | Restricted |
| Kansas | Class A | Spotted knapweed | Prohibited/Eradication |
| Kentucky | Noxious | Spotted knapweed | Invasive herb |
| Michigan | Prohibited | Spotted Knapweed | Biennial forb |
| Montana | Priority 2A | Spotted Knapweed | Common in isolated areas |
| Nebraska | Class 2 | Spotted Knapweed | |
| Nevada | Class B | Spotted Knapweed | Scattered populations |
| New Hampshire | Prohibited | Spotted Knapweed | Invasive herb |
| New Jersey | Noxious Weed | Spotted Knapweed | Prohibited seed |
| New Mexico | Class B | Spotted Knapweed | Biennial/perennial |
| New York | Prohibited | Spotted Knapweed | Biennial/perennial |
| North Dakota | Prohibited | Spotted Knapweed | Biennial/perennial |
| Ohio | Prohibited | Spotted Knapweed | Biennial/perennial |
| Oklahoma | Noxious | Spotted Knapweed | Biennial/perennial |
| Rhode Island | Invasive | Spotted Knapweed | Biennial/perennial |
| Wyoming | Designated | Spotted knapweed | Biennial |
Data compiled from individual state Department of Agriculture noxious weed lists.
Verify against current official state sources before regulatory use.
| U.S. Noxious Weed Database — generated April 2026.