Noxious Weed Identification

Identification & Control

Colorado is seeing a dramatic increase in noxious weeds. Left uncontrolled, noxious weeds will form dense mono-cultures and displace native and desirable plants. Native plant loss affects wildlife that depends on the native vegetation for survival.

Please select from the following to find detailed information on the weed in which you’re interested.

Plants A - C


Arundo on creekbank.

Black Henbane

Small Black henbane plant.


Bouncingbet - white.

Bull Thistle

Bull thistle flower.

Canada Thistle

Canada thistle flower.


Cheatgrass plant.


Chicory flower.

Chinese Clematis

Chinese clematis seedhead.

Common Mullein

Common mullein rosette.

Common Tansy

Common tansy flowers.

Cypress Spurge

Cypress spurge plants.

Plants D - K

Dalmatian Toadflax

Dalmatian toadflax flower.

Dames Rocket

Dames rocket flower.

Diffuse Knapweed

Diffuse knapweed seedheads.

Dyer's Woad

Dyers woad seed.

Field Bindweed

Field bindweed flowers.

Hairy Willow-Herb

Hairy willow herb flower.

Hoary Cress

Hoary cress plants.


Houndstongue seed.


Knotweed plant showing leaves and flowers.

Plants L - R

Leafy Spurge

Leafy spurge flower.

Moth Mullein

Moth mullein flower.

Musk Thistle

Musk thistle flowers.

Myrtle Spurge

Myrtle spurge flower.

Orange Hawkweed

Orange hawkweed flower.

Oxeye Daisy

Oxeye daisy flower.

Perennial Pepperweed

Perennial pepperweed flower.

Plumeless Thistle

Plumeless thistle flower.

Poison Hemlock

Poison hemlock flowers.

Purple Loosestrife

Purple loosestrife flower.

Russian Knapweed

Russian knapweed flower.

Russian Olive

Russian olive fruit.

Plants S - Z

Saltcedar - Tamarisk

Tamarisk flower.

Scentless Chamomile

Chamomile flower.

Scotch Thistle

Scotch thistle plant.

Spotted Knapweed

Spotted knapweed flower.

Sulfur Cinquefoil

Sulfur cinquefoil flower.


Teasel seedhead.

Yellow Starthistle

Yellow starthistle flower.

Yellow Toadflax

Yellow toadflax plant.