Montana Noxious Weed Information

dalmatian toadflax, spotted knapweed, yellowflag iris

Montana Noxious Weed List (Updated July 2015)

Some counties have additional weeds on their county noxious weed list.

Click here to download a reference guide for noxious weed management published by the USDA Natural Resources Conservation Service.


Priority 1A:

These weeds are not present or have a very limited presence in Montana. Management criteria will require eradication if detected, education, and prevention.

Priority 1B:

These weeds have limited presence in Montana. Management criteria will require eradication or containment and education.

Priority 2A:

These weeds are common in isolated areas of Montana. Management criteria will require eradication or containment where less abundant. Management shall be prioritized by local weed districts.

Priority 2B:

These weeds are abundant in Montana and widespread in many counties. Management criteria will require eradication or containment where less abundant. Management shall be prioritized by local weed districts.

Priority 3: Regulated Plants: (NOT MONTANA LISTED NOXIOUS WEEDS)

These regulated plants have the potential to have significant negative impacts. The plant may not be intentionally spread or sold other than as a contaminant in agricultural products. The state recommends research, education and prevention to minimize the spread of the regulated plant.

  • Cheatgrass (Bromus tectorum)
  • Hydrilla (Hydrilla verticillata)
  • Russian olive (Elaeagnus angustifolia)
  • Brazilian waterweed (Egeria densa)
  • Parrot feather watermilfoil (Myriophyllum aquaticum or M. brasiliense)