Washington State Noxious Weed Control Board

Class B Noxious Weeds

Class B noxious weeds are nonnative species whose distribution is limited to portions of Washington State.

Species are designated for control in state regions where they are not yet widespread. Prevention of new infestations in these areas is the primary goal.
In regions where a Class B species is already abundant, control is decided at the local level. Containment of these weeds is the primary goal so that they do not spread into un-infested regions.
Please contact your County Weed Board to learn which species are designated in your area, or click here to see a map of Regions with links to the Class B Designates for each Region.


Austrian fieldcress Rorripa austriaca	blackgrass Alopecurus myosuroides	blueweed Echium vulgare	Brazilian elodea Egeria densa	bugloss, annual Anchusa arvensis

bugloss, common Anchusa officinalis	butterfly bush buddleia davidii	camelthorn Alhagi maurorum	common catsear Hypochaeris radicata	common fennel Foeniculum vulgare

common reed Phragmites australis	cordgrass, smooth Spartina alterniflora	Dalmatian toadflax Linaria dalmatica ssp. dalmatica	Eurasian watermilfoil Myriophyllum spicatum	fanwort Cabomba caroliniana

gorse Ulex europaeus	grass-leaved arrowhead Sagittaria graminea	hawkweed oxtongue Picris hieracioides	hawkweed, mouseear Hieracium pilosella	hawkweed, orange Hieracium aurantiacum

hawkweed, polar Hieracium atratum	hawkweed, queen-devil Hieracium glomeratum	hawkweed, smooth Hieracium laevigatum	hawkweed, yellow Hieracium caespitosum	herb-Robert Geranium robertianum

hoary alyssum Berteroa incana	houndstongue Cynoglossum officinale	indigobush Amorpha fruticosa	knapweed, black Centaurea nigra	knapweed, brown Centaurea jacea


knapweed, diffuse Centaurea diffusa	knapweed, meadow, Centaurea jacea x nigra	knapweed, Russian Acroptilon repens	knapweed, spotted Centaurea stoebe	knotweed, Bohemian Polygonum bohemicum

knotweed, giant Polygonum sachalinense	knotweed, Himalayan Polygonum polystachyum	knotweed, Japanese Polygonum cuspidatum	Kochia Kochia scoparia	lawnweed Soliva sessilis
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lepyrodiclis Lepyrodiclis holosteoides	longspine sandbur Cenchrus longispinus	loosestrife, garden Lysimachia vulgaris	loosestrife, purple Lythrum salicaria	loosestrife, wand Lythrum virgatum

oxeye daisy Leucanthemum vulgare	parrotfeather Myriophyllym aquaticum	perennial pepperweed Lepidum latifolium	perennial sowthistle Sonchus arvensis spp. arvensis	policeman's helmet Impatiens glandulifera

poison-hemlock Conium maculatum	puncturevine Tribulus terrestris	rush skeletonweed Chondrilla juncea	saltcedar Tamarix ramosissima	Scotch broom Cytisus scoparius


spurge laurel Daphne laureola	spurge, leafy Euphorbia esula	spurge, myrtle Euphorbia myrsinites	sulfur cinquefoil Potentilla recta	swainsonpea Sphaerophysa salsula

tansy ragwort Senecio jacobaea	thistle, musk Carduus nutans	thistle, plumeless Carduus acanthoides	thistle, Scotch Onopordum acanthium	water primrose Ludwigia hexapetala

white bryony Bryonia alba	wild chervil Anthriscus sylvestris	wild carrot Daucus carota	yellow floating heart Nymphoides peltata	yellow nutsedge Cyperus esculentus

yellow starthistle Centaurea solstitialis