Noxious Weed List

Priority 1A

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

  • Common reed (Phragmites australis ssp. australis)
  • Dyer's woad (Isatis tinctoria)
  • Medusahead (Taeniatherum caput-medusae)
  • Yellow starthistle (Centaurea solstitialis)

Priority 1B

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

  • Blueweed (Echium vulgare) 
  • Knotweed complex (Polygonum cuspidatum, P. sachalinense, P. x bohemicum, Fallopia japonica, F. sachalinensis, F. x bohemica, Reynoutria japonica, R. sachalinensis, and R. x bohemica)
  • Purple loosestrife (Lythrum spp.)
  • Rush skeletonwed (Chondrilla juncea)
  • Scotch broom (Cytisus scoparius) 

Priority 2A

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

  • Eurasian watermilfoil (Myriophyllum spicatum, Myriophyllum spicatum x, Myriophyllum sibricum)
  • Flowering rush (butomus umbellatus) 
  • Meadow hawkweed complex (Hieracium spp.)
  • Orange hawkweed (Hieracium aurantiacum) 
  • Perennial pepperweed (Lepidium latifolium)
  • Tall buttercup (Ranunculus acris)
  • Tansy ragwort (Senecio jacobaea) 
  • Ventenata (Ventenata dubia)
  • Yellowflag iris (Iris pseudacorus)

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.

  • Canada thistle (Cirsium arvense) 
  • Common buckthorn (rhamnus cathartica L.)
  • Common tansy (Tanacetum vulgare) 
  • Curlyleaf pondweed (Potamogeton crispus)
  • Dalmatian toadflax (Linaria dalmatica)
  • Diffuse knapweed (Centaurea diffusa)
  • Field bindweed (Convolvulus arvensis) 
  • Hoary alyssum (Berteroa incana) 
  • Houndstongue (Cynoglossum officinale) 
  • Leafy Spurge (Euphorbia esula) 
  • Oxeye Daisy (Leucanthemum vulgare) 
  • Russian Knapweed (Acroptilon repens)
  • Saltcedar (Tamarix spp.) 
  • Spotted Knapweed (Centaurea stoebe)
  • St. Johnswort (Hypericum perforatum)
  • Sulfur Cinquefoil (Potentilla recta)
  • Whitetop (Cardaria draba, Lepidium draba)
  • Yellow Toadflax (Linaria vulgaris)

Priority 3

Regulated Plants: Not Montana listed noxious weeds. These regulated plants have the potential to have significant negative impacts. The plants 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.

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