Priority 1A

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

  1. Yellow starthistle (Centaurea solstitialis)
  2. Dyer's woad (Isatis tinctoria)
  3. Common Reed (Phragmites australis ssp. australis)

Priority 1B

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

  1. Knotweed complex (Polygonum cuspidatum, P. sachalinense, P. bohemicum, Fallopia japonica, F. sachalinensis, F. bohemica, Reynoutria japonica, R. sachalinensis and R. bohemica)
  2. Purple loosestrife (Lythrum salicaria)
  3. Rush skeletonweed (Chondrilla juncea)
  4. Scotch broom (Cytisus scoparius)

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.

  1. Tansy ragwort (Senecio jacobaea, Jacobaea vulgaris)
  2. Meadow hawkweed complex (Hieracium caespitosum, H. praealturm, H. floridundum and Pilosella caespitosa)
  3. Orange hawkweed (Hieracium aurantiacum, Pilosella aurantiaca)
  4. Tall buttercup (Ranunculus acris)
  5. Perennial pepperweed (Lepidium latifolium)
  6. Yellowflag iris (Iris pseudacorus)
  7. Blueweed (Echium vulgare)
  8. Eurasian watermilfoil (Myriophyllum spicatum)
  9. Flowering rush (Butomus umbellatus)

Priority 2B

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

  1. Canada thistle (Cirsium arvense)
  2. Field bindweed (Convolvuus arvensis)
  3. Leafy spurge (Euphorbia esula)
  4. Whitetop (Cardaria draba, Lepidium draba)
  5. Russian knapweed (Acroptilon repens, Rhaponticum repens)
  6. Spotted knapweed (Centaurea stoebe, C. maculosa)
  7. Diffuse knapweed (Centaurea diffusa)
  8. Dalmatian toadflax (Linaria dalmatica)
  9. St. Johnswort (Hypericum perforatum)
  10. Sulfur sinquefoil (Potentilla recta)
  11. Common tansy (Tanacetum vulgare)
  12. Oxeye daisy (Leucanthemum vulgare)
  13. Houndstongue (Cynoglossum officinale)
  14. Yellow toadflax (Linaria vulgaris)
  15. Saltcedar (Tamarix spp.)
  16. Curlyleaf pondweed (Potamogeton crispus)
  17. Hoary alyssum (Berteroa incana)

Priority 3 (Regulated Plants)

These are 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 a regulated plant.

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