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 )

Dalmation 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 )


( Cardaria draba, Lepidiuim draba )

Yellow Startthistle

( Centaurea solstitialis )

Yellow Toadflax

( Linaria vulgaris )

Yellowflag Iris

( Iris pseudacorus )

Featured Video

It’s been a long winter, but the weeds are popping up!! Before you know it, you’ll need to get your ATV out and start treating weeds. In case you need a refresher, here is a valuable video on how to calibrate your ATV. Thanks to Elkhorn Productions, Ravalli County and the MDA Trust Fund grant that produced this.

Upcoming Events

Upcoming Events

2019 Weed Whackers Ball will be September 14th in Wise River! Come attend the greatest Weed Party in Montana! More details TBA!