Clark County Noxious Weed List
Clark County Noxious Weed List - Adopted February 2, 2026
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Class A Weeds: Non-native species whose distribution in Washington is still limited. Preventing new infestations and eradicating existing infestations are the highest priority. Eradication of all Class A plants is required by law.
| Common Name | Scientific Name | Class |
|---|---|---|
| common crupina | Crupina vulgaris | A |
| cordgrass, common | Spartina anglica | A |
| cordgrass, dense-flowered | Spartina densiflora | A |
| cordgrass, saltmeadow | Spartina patens | A |
| cordgrass, smooth | Spartina alterniflora | A |
| delta arrowhead | Sagittaria platyphylla | A |
| dyer’s woad | Isatis tinctoria | A |
| eggleaf spurge | Euphorbia oblongata | A |
| false brome | Brachypodium sylvaticum | A |
| floating primrose-willow | Ludwigia peploides | A |
| flowering rush | Butomus umbellatus | A |
| French broom | Genista monspessulana | A |
| garlic mustard | Alliaria petiolata | A |
| giant hogweed | Heracleum mantegazzianum | A |
| goatsrue | Galega officinalis | A |
| hydrilla | Hydrilla verticillata | A |
| Johnsongrass | Sorghum halepense | A |
| knapweed, bighead | Centaurea macrocephala | A |
| knapweed, Vochin | Centaurea nigrescens | A |
| kudzu | Pueraria montana var. lobata | A |
| meadow clary | Salvia pratensis | A |
| oriental clematis | Clematis orientalis | A |
| Palmer amaranth | Amaranthus palmeri | A |
| purple starthistle | Centaurea calcitrapa | A |
| reed sweetgrass | Glyceria maxima | A |
| ricefield bulrush | Schoenoplectus mucronatus | A |
| round leaf bittersweet | Celastrus orbiculatus | A |
| sage, clary | Salvia sclarea | A |
| sage, Mediterranean | Salvia aethiopis | A |
| silverleaf nightshade | Solanum elaeagnifolium | A |
| small-flowered jewelweed | Impatiens parviflora | A |
| South American spongeplant | Limnobium laevigatum | A |
| Spanish broom | Spartium junceum | A |
| Sunflower broomrape | Orobanche cumana | A |
| Syrian beancaper | Zygophyllum fabago | A |
| Texas blueweed | Helianthus ciliaris | A |
| thistle, Italian | Carduus pycnocephalus | A |
| thistle, marsh | Cirsium palustre | A |
| thistle, milk | Silybum marianum | A |
| thistle, slenderflower | Carduus tenuiflorus | A |
| thistle, Turkish | Carduus cinereus | A |
| variable-leaf milfoil & hybrid | Myriophyllum heterophyllum, M. heterophyllum x M. hippuroides | A |
| waterhemp | Amaranthus tuberculatus | A |
| wild four-o'clock | Mirabilis nyctaginea | A |
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Class B Weeds: Non-native species presently limited to portions of the State. Species are designated for required control in regions where they are not yet widespread. Preventing new infestations in these areas is a high priority. In regions where a Class B species is already abundant, control is decided at the local level, with containment as the primary goal.
| Common Name | Scientific Name | Class |
|---|---|---|
| blueweed | Echium vulgare | B |
| Brazilian elodea | Egeria densa | B |
| bugloss, annual | Lycopsis arvensis | B |
| bugloss, common | Anchusa officinalis | B |
| butterfly bush (Control not mandated unless within 100' of natural waterbody) | Buddleja davidii | B |
| camelthorn | Alhagi maurorum | B |
| common reed (nonnative genotypes only) | Phragmites australis | B |
| common tansy | Tanacetum vulgare | B |
| Dalmatian toadflax | Linaria dalmatica ssp. dalmatica | B |
| Eurasian watermilfoil (Control mandated unless within 100' of Columbia River) | Myriophyllum spicatum | B |
| European coltsfoot | Tussilago farfara | B |
| fanwort | Cabomba caroliniana | B |
| gorse | Ulex europaeus | B |
| grass-leaved arrowhead | Sagittaria graminea | B |
| hairy willowherb | Epilobium hirsutum | B |
| hanging sedge | Carex pendula, C. pendula subsp. pendula and C. pendula subsp. agastachys | B |
| hawkweed oxtongue | Picris hieracioides | B |
| hawkweed, orange | Hieracium aurantiacum | B |
| hawkweeds: All nonnative species & hybrids of the meadow subgenus | Hieracium, subgenus Pilosella | B |
| hawkweeds: All nonnative species & hybrids of the wall subgenus | Hieracium, subgenus Hieracium | B |
| hoary alyssum | Berteroa incana | B |
| houndstongue | Cynoglossum officinale | B |
| knapweed, black | Centaurea nigra | B |
| knapweed, brown | Centaurea jacea | B |
| knapweed, diffuse | Centaurea diffusa | B |
| knapweed, meadow (Control not mandated unless within 100' of neighboring property producing agriculture) | Centaurea × gerstlaueri | B |
| knapweed, Russian | Rhaponticum repens | B |
| knapweed, spotted | Centaurea stoebe | B |
| knotweed, Bohemian | Fallopia × bohemica | B |
| knotweed, giant | Fallopia sachalinensis | B |
| knotweed, Himalayan | Persicaria wallichii | B |
| knotweed, Japanese | Fallopia japonica | B |
| kochia | Bassia scoparia | B |
| lesser celandine | Ficaria verna | B |
| loosestrife, garden | Lysimachia vulgaris | B |
| loosestrife, purple | Lythrum salicaria | B |
| loosestrife, wand | Lythrum virgatum | B |
| Malta starthistle | Centaurea melitensis | B |
| parrotfeather | Myriophyllum aquaticum | B |
| poison hemlock | Conium maculatum | B |
| policeman’s helmet | Impatiens glandulifera | B |
| puncturevine | Tribulus terrestris | B |
| Ravenna grass | Tripidium ravennae | B |
| rough chervil | Chaerophyllum temulum | B |
| rush skeletonweed | Chondrilla juncea | B |
| saltcedar | Tamarix ramosissima | B |
| Scotch broom (Control not mandated unless within 100' of neighboring property producing agriculture) | Cytisus scoparius | B |
| shiny geranium (Control not mandated unless within 100' of neighboring property producing agriculture) | Geranium lucidum | B |
| spurge flax | Thymelaea passerina | B |
| spurge laurel | Daphne laureola | B |
| spurge, leafy | Euphorbia virgata | B |
| spurge, myrtle | Euphorbia myrsinites | B |
| sulfur cinquefoil | Potentilla recta | B |
| tansy ragwort | Jacobaea vulgaris | B |
| thistle, musk | Carduus nutans | B |
| thistle, plumeless | Carduus acanthoides | B |
| thistle, Scotch | Onopordum acanthium | B |
| velvetleaf | Abutilon theophrasti | B |
| water primrose | Ludwigia hexapetala | B |
| white bryony | Bryonia alba | B |
| wild basil | Clinopodium vulgare | B |
| wild chervil | Anthriscus sylvestris | B |
| yellow floating heart | Nymphoides peltata | B |
| yellow nutsedge | Cyperus esculentus | B |
| yellow starthistle | Centaurea solstitialis | B |
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Class C Weeds: Noxious weeds that are typically widespread in WA or are of special interest to the state’s agricultural industry. The Class C status allows county weed boards to require control if locally desired, or they may choose to provide education or technical consultation.
| Common Name | Scientific Name | Class |
|---|---|---|
| absinth wormwood | Artemisia absinthium | C |
| babysbreath | Gypsophila paniculata | C |
| black henbane | Hyoscyamus niger | C |
| black locust | Robinia pseudoacacia | C |
| buffalobur | Solanum rostratum | C |
| common holly, except where commercially grown | Ilex aquifolium | C |
| fragrant waterlily | Nymphaea odorata | C |
| hairy whitetop | Lepidium appelianum | C |
| hoary cress | Lepidium draba | C |
| medusahead | Taeniatherum caput-medusae | C |
| Norway maple | Acer platanoides | C |
| Russian olive | Elaeagnus angustifolia | C |
| spikeweed | Centromadia pungens | C |
| thistle, bull (Control not mandated unless within 100' of neighboring property producing agriculture) | Cirsium vulgare | C |
| thistle, Canada (Control not mandated unless within 100' of neighboring property producing agriculture) | Cirsium arvense | C |
| yellow flag iris | Iris pseudacorus | C |
To learn more about noxious weeds and noxious weed control in Washington State and Clark County, please contact:
NOXIOUS WEED MANAGEMENT · CLARK COUNTY
PUBLIC WORKS · NOXIOUS WEED CONTROL BOARD
4700 NE 78th Street Building G ∙ Vancouver, WA 98665
564.397.6140 ∙ weed.board@clark.wa.gov
For other formats, contact the Clark County ADA Office
Voice: 564.397.2322 / Relay: 711 or 800.833.6388
Fax: 564.397.6165 / Email: ADA@clark.wa.gov
WA State Noxious Weed Control Board
360.725.5764 ∙ noxiousweeds@agr.wa.gov
http://www.nwcb.wa.gov