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Noxious Weeds of Colorado

Noxious weeds are non-native plant species that grow in areas where they have not historically occurred. This can be very disruptive to native vegetation and entire ecosystems. They can be damaging to native species, drinking water, agriculture, and natural habitats.

This is a guide ...more ↓

Giant Salvinia ¹
Salvinia molesta

Scotch Broom ²
Cytisus scoparius

Sericea Lespedeza ³
Lespedeza cuneata

Swainsonpea ⁴
Sphaerophysa salsula

Camelthorn ⁵
Alhagi maurorum

Sulphur Cinquefoil ⁶
Potentilla recta

Himalayan Blackberry ⁷
Rubus armeniacus

Siberian elm ⁸
Ulmus pumila

Russian Olive ⁹
Elaeagnus angustifolia

Garden Loosestrife ¹⁰
Lysimachia vulgaris

Japanese Knotweed ¹¹
Fallopia japonica

Giant Knotweed ¹²
Fallopia sachalinensis

Bohemian Knotweed ¹³
Fallopia x Bohemica

Bouncingbet ¹⁴
Saponaria officinalis

Baby's Breath ¹⁵
Gypsophila paniculata

Five-stamen Tamarisk ¹⁶
Tamarix chinensis

Small-flowered Tamarisk ¹⁷
Tamarix parviflora

Red Tamarisk ¹⁸
Tamarix ramosissima

Halogeton ¹⁹
Halogeton glomeratus

Canada Thistle ²⁰
Cirsium arvense

Bull Thistle ²¹
Cirsium vulgare

Plumeless Thistle ²²
Carduus acanthoides

Musk Thistle ²³
Carduus nutans

Common Burdock ²⁴
Arctium minus

Scotch Thistle ²⁵
Onopordum acanthium

Yellow Starthistle ²⁶
Centaurea solstitialis

Monckton's Knapweed ²⁷
Centaurea × moncktonii

Hybrid Knapweed ²⁸
Centaurea x psammogena

Diffuse knapweed ²⁹
Centaurea diffusa

Spotted Knapweed ³⁰
Centaurea stoebe

Squarrose Knapweed ³¹
Centaurea virgata

Russian Knapweed ³²
Acroptilon repens

Common Crupina ³³
Crupina vulgaris

Rush Skeletonweed ³⁴
Chondrilla juncea

Chicory ³⁵
Cichorium intybus

Orange Hawkweed ³⁶
Hieracium aurantiacum

Meadow Hawkweed ³
Hieracium caespitosum

Perennial Sowthistle ³⁷
Sonchus arvensis

Oxeye Daisy ³⁸
Leucanthemum vulgare

Mayweed Chamomile ³⁹
Anthemis cotula

Scentless Chamomile ⁴⁰
Tripleurospermum inodorum

Common Tansy ⁴¹
Tanacetum vulgare

Absinth Wormwood ³⁰
Artemisia absinthium

Tansy Ragwort ⁴²
Jacobaea vulgaris

Redstem Filaree ⁴³
Erodium cicutarium

tree-of-heaven ⁴⁴
Ailanthus altissima

African Rue ⁴⁵
Peganum harmala

Hairy Willow-herb ⁴⁶
Epilobium hirsutum

Purple Loosestrife ³⁵
Lythrum salicaria

Moth Mullein ³⁰
Verbascum blattaria

Common Mullein ⁴⁷
Verbascum thapsus

Mediterranean Sage ⁴⁸
Salvia aethiopis

Dalmatian Toadflax ¹⁶
Linaria dalmatica

Yellow Toadflax ⁴⁹
Linaria vulgaris

Chinese Clematis ⁵⁰
Clematis orientalis

Henbane ⁵¹
Hyoscyamus niger

Hybrid Toadflax ²⁸
Linaria vulgaris x L. dalmatica

Field Bindweed ⁵²
Convolvulus arvensis

Common Teasel ⁵³
Dipsacus fullonum

Cutleaf Teasel ⁹
Dipsacus laciniatus

Wild Caraway ⁵⁴
Carum carvi

Poison Hemlock ⁵⁵
Conium maculatum

Velvetleaf ⁵⁶
Abutilon theophrasti

Cypress Spurge ⁵⁷
Euphorbia cyparissias

Leafy Spurge ³⁰
Euphorbia esula

Myrtle spurge ⁴¹
Euphorbia myrsinites

Common St. Johnswort ⁵⁸
Hypericum perforatum

Common Bugloss ⁵⁹
Anchusa officinalis

Houndstongue ³⁵
Cynoglossum officinale

Syrian Bean-Caper ⁶⁰
Zygophyllum fabago

Puncturevine ⁶¹
Tribulus terrestris

Elongated Mustard ⁶²
Brassica elongata

Hoary Alyssum ⁶³
Berteroa incana

Heart-podded Hoary Cress ⁶⁴
Lepidium draba

Perennial Pepperweed ⁶⁵
Lepidium latifolium

Garlic Mustard ⁶⁶
Alliaria petiolata

Dame's Rocket ⁶⁷
Hesperis matronalis

Dyer's Woad ³⁰
Isatis tinctoria

White Bryony ⁶⁸
Bryonia alba

Parrot's Feather ⁶⁹
Myriophyllum aquaticum

Eurasian Watermilfoil ⁷⁰
Myriophyllum spicatum

Yellow Nutsedge ⁷¹
Cyperus esculentus

Proso Millet ³⁴
Panicum miliaceum

Caucasian Bluestem ⁷²
Bothriochloa bladhii

Yellow bluestem ⁷³
Bothriochloa ischaemum

Johnsongrass ⁷⁴
Sorghum halepense

Bulbous Bluegrass ⁷⁵
Poa bulbosa

Ventenata Grass ⁷⁶
Ventenata dubia

Cheatgrass ⁷⁷
Bromus tectorum

Quack Grass ³⁰
Elymus repens

Medusa Head ⁷⁸
Taeniatherum caput-medusae

Jointed Goatgrass ⁷⁹
Aegilops cylindrica

Giant Reed ⁷⁴
Arundo donax

Common Reed ⁸⁰
Phragmites australis

Yellow Flag Iris ⁸¹
Iris pseudacorus

Onionweed ⁸²
Asphodelus fistulosus

Hydrilla ⁸³
Hydrilla verticillata

Flowering Rush ⁸⁴
Butomus umbellatus

Edited by Colorado Parks and Wildlife, some rights reserved (CC BY-SA)

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Noxious Weeds of Colorado

Giant Salvinia 1 Salvinia molesta

Scotch Broom 2 Cytisus scoparius

Sericea Lespedeza 3 Lespedeza cuneata

Swainsonpea 4 Sphaerophysa salsula

Camelthorn 5 Alhagi maurorum

Sulphur Cinquefoil 6 Potentilla recta

Himalayan Blackberry 7 Rubus armeniacus

Siberian elm 8 Ulmus pumila

Russian Olive 9 Elaeagnus angustifolia

Garden Loosestrife 10 Lysimachia vulgaris

Japanese Knotweed 11 Fallopia japonica

Giant Knotweed 12 Fallopia sachalinensis

Bohemian Knotweed 13 Fallopia x Bohemica

Bouncingbet 14 Saponaria officinalis

Baby's Breath 15 Gypsophila paniculata

Five-stamen Tamarisk 16 Tamarix chinensis

Small-flowered Tamarisk 17 Tamarix parviflora

Red Tamarisk 18 Tamarix ramosissima

Halogeton 19 Halogeton glomeratus

Canada Thistle 20 Cirsium arvense

Bull Thistle 21 Cirsium vulgare

Plumeless Thistle 22 Carduus acanthoides

Musk Thistle 23 Carduus nutans

Common Burdock 24 Arctium minus

Scotch Thistle 25 Onopordum acanthium

Yellow Starthistle 26 Centaurea solstitialis

Monckton's Knapweed 27 Centaurea × moncktonii

Hybrid Knapweed 28 Centaurea x psammogena

Diffuse knapweed 29 Centaurea diffusa

Spotted Knapweed 30 Centaurea stoebe

Squarrose Knapweed 31 Centaurea virgata

Russian Knapweed 32 Acroptilon repens

Common Crupina 33 Crupina vulgaris

Rush Skeletonweed 34 Chondrilla juncea

Chicory 35 Cichorium intybus

Orange Hawkweed 36 Hieracium aurantiacum

Meadow Hawkweed 3 Hieracium caespitosum

Perennial Sowthistle 37 Sonchus arvensis

Oxeye Daisy 38 Leucanthemum vulgare

Mayweed Chamomile 39 Anthemis cotula

Scentless Chamomile 40 Tripleurospermum inodorum

Common Tansy 41 Tanacetum vulgare

Absinth Wormwood 30 Artemisia absinthium

Tansy Ragwort 42 Jacobaea vulgaris

Redstem Filaree 43 Erodium cicutarium

tree-of-heaven 44 Ailanthus altissima

African Rue 45 Peganum harmala

Hairy Willow-herb 46 Epilobium hirsutum

Purple Loosestrife 35 Lythrum salicaria

Moth Mullein 30 Verbascum blattaria

Common Mullein 47 Verbascum thapsus

Mediterranean Sage 48 Salvia aethiopis

Dalmatian Toadflax 16 Linaria dalmatica

Yellow Toadflax 49 Linaria vulgaris

Chinese Clematis 50 Clematis orientalis

Henbane 51 Hyoscyamus niger

Hybrid Toadflax 28 Linaria vulgaris x L. dalmatica

Field Bindweed 52 Convolvulus arvensis

Common Teasel 53 Dipsacus fullonum

Cutleaf Teasel 9 Dipsacus laciniatus

Wild Caraway 54 Carum carvi

Poison Hemlock 55 Conium maculatum

Velvetleaf 56 Abutilon theophrasti

Cypress Spurge 57 Euphorbia cyparissias

Leafy Spurge 30 Euphorbia esula

Myrtle spurge 41 Euphorbia myrsinites

Common St. Johnswort 58 Hypericum perforatum

Common Bugloss 59 Anchusa officinalis

Houndstongue 35 Cynoglossum officinale

Syrian Bean-Caper 60 Zygophyllum fabago

Puncturevine 61 Tribulus terrestris

Elongated Mustard 62 Brassica elongata

Hoary Alyssum 63 Berteroa incana

Heart-podded Hoary Cress 64 Lepidium draba

Perennial Pepperweed 65 Lepidium latifolium

Garlic Mustard 66 Alliaria petiolata

Dame's Rocket 67 Hesperis matronalis

Dyer's Woad 30 Isatis tinctoria

White Bryony 68 Bryonia alba