Weed ID

This field guide is designed to help you identify Montana’s 35 state listed noxious weeds and regulated plants. Each plant review includes the photos and the 10 characteristics defined to your right.

If you believe you have found a noxious weed, please contact your county weed district or tribal area office. They can help you with a management plan, offer best practices on control and eradication and, in some counties, they provide cost-share programs to assist you with management.

Lets get started! Find Your Weed

Click on photos for plant details …


( Echium vulgare )

Brazilian Waterweed

( Egeria densa )

Canada Thistle

( Cirsium arvense )


( Bromous tectorum )

Common Buckthorn

( Rhamnus cathartica L )

Common Reed

( Phragmites australis )

Common Tansy

( Tanacetum vulgare )

Curly Leaf Pondweed

( Potamogeton crispus )

Dalmatian Toadflax

( Linaria dalmatica )

Diffuse Knapweed

( Centaurea diffusa )

Dyer’s Woad

( Isatis tinctoria )

Eurasian Watermilfoil

( Myriophyllum spicatum )

Field Bindweed

( Convolvulus arvensis )

Flowering Rush

( Butomus umbellatus )

Hoary Alyssum

( Berteroa incana )


( Cynoglossum officinale )


( Hydrilla verticillata )

Knotweed Complex

( Reynoutria japonica+ )

Leafy Spurge

( Euphorbia esula )

Meadow Hawkweed Complex

( Hieracium caespitosum )


( Taeniatherum caput-medusa )

Orange Hawkweed

( Hieracium aurantiacum )

Oxeye Daisy

( Leuconthemum vulgare )


( Myriophyllum aquaticum )

Perennial Pepperweed

( Lepidium latifolium )

Purple Loosestrife

( Lythrum salicaria )

Rush Skeletonweed

( Chondrilla juncea )

Russian Knapweed

( Acroptilon repens, Rhaponticum repens )

Russian Olive

( Elaeagnus angustfolia )


( Tamarix ramosissima, T. chinensis )

Scotch Broom

( Cytisus scoparius )

Spotted Knapweed

( Centaurea stoebe )

St. Johnswort

( Hypericum perforatum )

Sulfur Cinquefoil

( Potentilla recta )

Tall Buttercup

( Ranunculus acris )

Tansy Ragwort

( Senecio jacobaea, Jacobaea vulgaris )


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( Cardaria draba, Lepidiuim draba )

Yellow Startthistle

( Centaurea solstitialis )

Yellow Toadflax

( Linaria vulgaris )

Yellowflag Iris

( Iris pseudacorus )

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Upcoming Events

Upcoming Events

Montana Nonprofit Association Virtual Conference

Many CWMA’s across Montana are nonprofit-based and the Montana Nonprofit Association is an extremely valuable resource for any nonprofit, including MWCA. The week of September 21st, the MNA is hosting its first ever virtual conference. Many MWCA board members are attending, not only for the valuable knowledge, but to see how a virtual platform works for a major conference. In the past, MNA has had over 400 attendees at their in-person conferences.