Colorado's Weed List

This section is under construction.  Please visit again to view updated material.

The Colorado Noxious Weed Act and supporting Rules establish a prioritized list of noxious weeds.  For detailed information visit the State's site. 

A List

List A species are invasive weeds that are either not known to occur in Colorado or are of very limited distribution and are required to be eradicated.

African rue (Peganum harmala)

Camelthorn (Alhagi pseudalhagi)

Common crupina (Crupina vulgaris)

Cypress spurge (Euphorbia cyparissias)

Dyer's woad (Isatis tinctoria)

Giant salvinia (Salvinia molesta)

Hydrilla (Hydrilla verticillata)

Meadow knapweed (Centaurea pratensis)

Mediterranean sage (Salvia aethiopis)

Medusahead (Taeniatherum caput-medusae)

Myrtle spurge (Euphorbia myrsinites)

Orange hawkweed (Hieracium aurantiacum)

Purple loosestrife (Lythrum salicaria)

Rush skeletonweed (Chondrilla juncea)

Sericea lespedeza (Lespedeza cuneata)

Squarrose knapweed (Centaurea virgata)

Tansy ragwort (Senecio jacobaea)

Yellow starthistle (Centaurea solstitialis)

B List

List B species are invasive weeds with populations of varying distribution and densities within the state.  The level of mandated control is based on local conditions.  These weeds may require eradication within certain areas of the state. 

Absinth wormwood (Artemisia absinthium)

Black henbane (Hyoscyamus niger)

Bouncingbet (Saponaria officinalis)

Bull thistle (Cirsium vulgare)

Canada thistle (Cirsium arvense)

Chinese clematis (Clematis orientalis)

Common tansy (Tanacetum vulgare)

Common teasel (Dipsacus fullonum)

Corn chamomile (Anthemis arvensis)

Cutleaf teasel (Dipsacus laciniatus)

Dalmatian toadflax, broad-leaved (Linaria dalmatica)

Dalmatian toadflax, narrow-leaved (Linaria genistifolia)

Dame's rocket (Hesperis matronalis)

Diffuse knapweed (Centaurea diffusa)

Eurasian watermilfoil (Myriophyllum spicatum)

Hoary cress (Cardaria draba)

Houndstongue (Cynoglossum officinale)

Jointed goatgrass (Aegilops cylindrica)

Leafy spurge (Euphorbia esula)

Mayweed chamomile (Anthemis cotula)

Moth mullein (Verbascum blattaria)

Musk thistle (Carduus nutans)

Oxeye daisy (Chrysanthemum leucanthemum)

Perennial pepperweed (Lepidium latifolium)

Plumeless thistle (Carduus acanthoides)

Quackgrass (Elytrigia repens)

Russian knapweed (Acroptilon repens)

Russian-olive (Elaeagnus angustifolia)

Salt cedar (Tamarix chinensis, T.parviflora, and T. ramosissima)

Scentless chamomile (Matricaria perforata)

Scotch thistle (Onopordum acanthium)

Scotch thistle (Onopordum tauricum)

Spotted knapweed (Centaurea maculosa)

Spurred anoda (Anoda cristata)

Sulfur cinquefoil (Potentilla recta)

Venice mallow (Hibiscus trionum)

Wild caraway (Carum carvi)

Yellow nutsedge (Cyperus esculentus)

Yellow toadflax (Linaria vulgaris)

C List

List C species are widespread and common within the state.  They may pose a risk to agricultural lands and may be required to be controlled.

Chicory (Cichorium intybus)

Common burdock (Arctium minus)

Common mullein (Verbascum thapsus)

Common St. Johnswort (Hypericum perforatum)

Downy brome (Bromus tectorum)

Field bindweed (Convolvulus arvensis)

Halogeton (Halogeton glomeratus)

Johnsongrass (Sorghum halepense)

Perennial sowthistle (Sonchus arvensis)

Poison hemlock (Conium maculatum)

Puncturevine (Tribulus terrestris)

Velvetleaf (Abutilon theophrasti)

Wild proso millet (Panicum miliaceum)

Copyright © 2006-2009, Colorado Weed Management Association. 
This internet site may contain links to external Internet sites. CWMA does not in any manner express or implied, approve or promote, make any representation, or endorse any opinions expressed on any of these outside Web sites.

contact webmaster

last updated 06/09/2009