Noxious Weed Species ID

List A Species in Colorado that are designated by the Commissioner for eradication.

List B Species are species for which the Commissioner, in consultation with the state noxious weed advisory committee, local governments, and other interested parties, develops and implements state noxious weed management plans designed to stop the continued spread of these species.

List C Species are species for which the Commissioner, in consultation with the state noxious weed advisory committee, local governments, and other interested parties, will develop and implement state noxious weed management plans designed to support the efforts of local governing bodies to facilitate more effective integrated weed management on private and public lands. The goal of such plans will not be to stop the continued spread of these species but to provide additional education, research, and biological control resources to jurisdictions that choose to require management of List C species.

Watch List Species that have been determined to pose a potential threat to the agricultural productivity and environmental values of the lands of the state. The Watch List is intended to serve advisory and educational purposes only. Its purpose is to encourage the identification and reporting of these species to the Commissioner in order to facilitate the collection of information to assist the Commissioner in determining which species should be designated as noxious weeds. Colorado Watch List  

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Printable Full Noxious Weed List  


List A Species

Not Known In CO | Less Than 10 Known Populations More Than 10 Populations

Not Known In Colorado

Camelthorn

Alhagi pseudalhagi

Common crupina
Crupina vulgaris

Giant salvinia
Salvinia molesta

Hydrilla
Hydrilla verticillata

Medusahead
Taeniatherum caput-medusae

Parrotfeather
Myriophyllum aquaticum

Squarrose knapweed
Centaurea virgata
 
Less Than 10 Known Populations

African rue
Peganum harmala

Dyer's woad
Isatis tinctoria

Elongated mustard
Brassica elongata

Flowering rush
Butomus umbellatus

Meadow knapweed
Centaurea x moncktonii

Rush skeletonweed
Chondrilla juncea

Tansy ragwort
Senecio jacobaea

Yellow starthistle
Centaurea solstitialis
 
More Than 10 Populations in Colorado

Cypress spurge
Euphorbia cyparissias

Giant reed
Arundo donax
Hairy willow-herb
Hairy willow-herb
Epilobium hirsutum

Knotweeds
Japanese, Giant, and Bohemian

Mediterranean sage
Salvia aethiopis

Myrtle spurge
Euphorbia myrsinites

Orange hawkweed
Hieracium aurantiacum

Purple loosestrife
Lythrum salicaria
 

List B Species


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

Cutleaf teasel
Dipsacus laciniatus

Dalmatian toadflax
Linaria dalmatica & genistifolia

Dame's rocket
Hesperis matronalis

Diffuse knapweed
Centaurea diffusa

Eurasian watermilfoil
Myriophyllum spicatum

Hoary cress
Lepidium draba

Houndstongue
Cynoglossum officinale

Hybrid knapweed
Centaurea x psammogena = C. stoebe x C. diffusa

Hybrid toadflax
Linaria vulgaris x L. dalmatica

Jointed goatgrass
Aegilops cylindrica

Leafy spurge
Euphorbia esula

Mayweed chamomile
Anthemis cotula

Moth mullein
Verbascum blattaria

Musk thistle
Carduus nutans

Oxeye daisy
Leucanthemum vulgare

Perennial pepperweed
Lepidium latifolium

Plumeless thistle
Carduus acanthoides

Russian knapweed
Acroptilon repens

Russian olive
Elaeagnus angustifolia

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

Scentless chamomile
Tripleurospermum inodorum

Scotch thistle
Onopordum acanthium

Spotted knapweed
Centaurea stoebe

Sulfur cinquefoil
Potentilla recta

Wild caraway
Carum carvi

Yellow nutsedge
Cyperus esculentus

Yellow toadflax
Linaria vulgaris
 

List C Species


Chicory
Cichorium intybus

Common burdock
Arctium minus

Common mullein
Verbascum thapsus
Common St. Johnswort
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

Quackgrass
Elymus repens

Redstem filaree
Erodium cicutarium

Velvetleaf
Abutilon theophrasti

Wild-proso millet
Panicum miliaceum
 

Watch List Species

Baby's breath
Baby's breath
Gypsophila paniculata
Caucasian bluestem
Caucasian bluestem
Bothriochloa bladhii
Common bugloss
Common bugloss
Anchusa officinalis
Common reed
Common reed
Phragmites australis
Garlic mustard
Garlic mustard
Alliaria petiolata
Garden loosestrife
Garden loosestrife
Lysimachia vulgaris
Himalayan blackberry
Himalayan blackberry
Rubus armeniacus
Hoary Allysum
Hoary alyssum
Berteroa incana
Meadow hawkweed
Meadow hawkweed
Hieracium caespitosum
Onionweed
Onionweed
Asphodelus fistulosus
Siberian elm
Siberian elm
Ulmus pumila
Scotch broom
Scotch broom
Cytisus scoparius
Swainsonpea
Swainsonpea
Sphaerophysa salsula
Syrian beancaper
Syrian beancaper
Zygophyllum fabago

Tree of Heaven
Ailanthus altissima
Ventenata grass
Ventenata grass
Ventenata dubia
White bryony
White bryony
Bryonia alba
Yellow bluestem
Yellow bluestem
Bothriochloa ischaemum
Yellow flag iris
Yellow flag iris
Iris pseudacorus