What is a Noxious Weed?
Noxious weeds are defined as being any exotic plant species which may render land unfit for agriculture, forestry, livestock, wildlife or other beneficial uses or that may harm native plant communities.

Montana Priority 1A Weeds:
These species are not present, or have very limited presence in Montana.  State management criteria requires eradication if detected, as well as education and prevention efforts. To date, dyer's woad is the only Priority 1A species present in Missoula County.

 

Montana Priority 1B Weeds:
These species have a limited presence in Montana. Management criteria requires eradication if detected, as well as education and prevention efforts. Missoula County has limited infestation of blueweed, rush skeletonweed, purple loosestrife and knotweed complex.

BluweedBlueweed

small rushskeletonweedRush Skeletonweed

Purple Loosestrife Purple Loosestrife

KnotweedKnotweed Complex

 

Scotch BroomScotchbroom

 

Montana Priority 2A Weeds:
These species are common in isolated regions of Montana.  Management criteria requires eradication or containment where they are less abundant.  Management of these species are prioritized by the local county weed district. Missoula County has populations and places major emphasis on the management of orange hawkweed, perennial pepperweed, yellowflag iris and common buckthorn.

small tansyragwortTansy Ragwort

small meadowhawkweedHawkweed Complex

small orangehawkweedOrange Hawkweed

Tall ButtercupTall Buttercup

 

small perennialpepperweedPerennial Pepperweed

small yellowflagflowerYellowflag Iris

small eurasianwatermilfoilEurasian Watermilfoil

small floweringrushFlowering Rush

 

 

Montana Priority 2B Weeds:
These species are abundant in Montana and widespread in many counties. Management criteria requires eradication or containment where less abundant.  Management of these species are prioritized by the local county weed district.  Management of these species in Missoula County occurs through Cooperative Weed Management Areas and cost-share grants with local landowners.  There are also strong biological control systems established for leafy spurge, spotted and diffuse knapweeds and Dalmatian and yellow toadflax.

 

small canadathistle
Canada Thistle

small fieldbindweedField Bindweed

small leafyspurgeLeafy Spurge

small whitetopWhitetop

 

small russianknapweed
Russian Knapweed

small spottedknapweed
Spotted Knapweed

small diffuseknapweed
Diffuse Knapweed

small dalmatiantoadflax
Dalmatian Toadflax

 

small stjohnswort
St. Johnswort

small sulfurcinquefoil
Sulfur Cinquefoil

small commontansy
Common Tansy

small oxeyedaisy
Oxeye Daisy

 

small houndstongue
Houndstongue

commontoadflax
Yellow Toadflax

small tamarisk
Saltcedar

small curlyleafpondweed
Curlyleaf Pondweed

 

small hoaryalyssum
Hoary Alyssum

 

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