EFFECTIVE: June 21, 2019
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:
- Yellow starthistle (Centaurea solstitialis)
- Dyer’s woad (Isatis tinctoria)
- Common reed (Phragmites australis ssp. australis)
- Medusahead (Taeniatherum caput-medusae)
PRIORITY 1B
These weeds have limited presence in Montana. Management criteria will require eradication or containment and education:
- Knotweed complex (Polygonum cuspidatum, P. sachalinense, P. × bohemicum, Fallopia japonica, F. sachalinensis, F. × bohemica, Reynoutria japonica, R. sachalinensis, and R.× bohemica)
- Purple loosestrife (Lythrum salicaria)
- Rush skeletonweed (Chondrilla juncea)
- Scotch broom (Cytisus scoparius)
- Blueweed (Echium vulgare)
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:
- Tansy ragwort (Senecio jacobaea)
- Meadow hawkweed complex (Hieracium spp.)
- Orange hawkweed (Hieracium aurantiacum)
- Tall buttercup (Ranunculus acris)
- Perennial Pepperweed (Lepidium latifolium)
- Yellowflag iris (Iris pseudacorus)
- Eurasian watermilfoil (Myriophyllum spicatum, Myriophyllum spicatum x Myriophyllum
sibiricum) - Flowering rush (Butomus umbellatus)
- Common buckthorn (Rhamnus cathartica L.)
- Ventanata (Ventanata dubia)
PRIORITY 2B
These weeds are abundant 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)
- Field bindweed (Convolvulus arvensis)
- Leafy spurge (Euphorbia esula)
- Whitetop (Cardaria draba)
- Russian knapweed (Centaurea repens)
- Spotted knapweed (Centaurea stoebe or maculosa)
- Diffuse knapweed (Centaurea diffusa)
- Dalmatian toadflax (Linaria dalmatica)
- St. Johnswort (Hypericum perforatum)
- Sulfur cinquefoil (Potentilla recta)
- Common tansy (Tanacetum vulgare)
- Oxeye daisy (Chrysanthemum leucanthemum or Leucanthemum vulgare)
- Houndstongue (Cynoglossum officinale)
- Yellow toadflax (Linaria vulgaris)
- Saltcedar (Tamarix spp.)
- Curlyleaf pondweed (Potamogeton crispus)
- Hoary alyssum (Berteroa incana)
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)