Class B Weeds

These species are established in some regions of Washington, but are of limited distribution or not present in other regions of the state. Because of differences in distribution, treatment of Class B weeds varies between regions of the state. In regions where a Class B is unrecorded or of limited distribution, prevention of seed production is required.

In these areas, the weed is a "Class B designate," meaning it is designated for control by state law. In regions where a Class B species is already abundant or widespread, control is a local option. In these areas the weed is a "Class B non-designate," with containment, gradual reduction, and prevention of further spread being the chief goals

Washington State Noxious Weed List - Class B Weeds

Common Name
Scientific Name
Annual buglossAnchusa arvensis
Austrian fieldcressRorippa austriaca
Black knapweedCentaurea nigra
BlackgrassAlopecurus myosuroides
BlueweedEchium vulgare
Bohemian knotweedPolygonum bohemicum
Brazilian elodeaEgeria densa
Brown knapweedCentaurea jacea
CamelthornAlhagi maurorum
Common buglossAnchusa officinalis
Common catsearHypochaeris radicata
Common cordgrassSpartina anglica
Dalmatian toadflaxLinaria dalmatica ssp. Dalmatica
Diffuse knapweedCentaurea diffusa
Eurasian watermilfoilMyriophyllum spicatum
FanwortCabomba caroliniana
Garden loosestrifeLysimachia vulgaris
Giant knotweedPolygonum sachalinense
GorseUlex europaeus
Grass-leaved arrowheadSagittaria graminea
HedgeparsleyTorilis arvensis
Herb-robertGeranium robertianum
Himalayan knotweedPolygonum polystachyum
Hoary alyssumBerteroa incana
HoundstongueCynoglossum officinale
IndigobushAmorpha fruticosa
Japanese knotweedPolygonum cuspidatum
KochiaKochia scoparia
Leafy spurgeEuphorbia esula
LepyrodiclisLepyrodiclis holosteoides
Longspine sandburCenchrus longispinus
Meadow knapweedCentaurea pratensis
Mouseear hawkweedHieracium pilosella
Musk thistleCarduus nutans
Myrtle spurgeEuphorbia myrsinites
Orange hawkweedHieracium aurantiacum
Oxeye daisyLeucanthemum vulgare
Oxtongue hawkweedPicris hieracioides
ParrotfeatherMyriophyllum aquaticum
Perennial pepperweedLepidium latifolium
Perennial sowthistleSonchus arvensis
Plumeless thistleCarduus acanthoides
Polar hawkweedHieracium atratum
Policeman’s helmetImpatiens glandulifera
PuncturevineTribulus terrestris
Purple loosestrifeLythrum salicaria
Queendevil hawkweedHieracium glomeratum
Rush skeletonweedChondrilla juncea
Russian knapweedAcroptilon repens
SaltcedarTamarix ramosissima
Scotch broomCytisus scoparius
Scotch thistleOnopordum acanthium
Smooth cordgrassSpartina alterniflora
Smooth hawkweedHieracium laevigatum
Spotted knapweedCentaurea biebersteinii
Sulfur cinquefoilPotentilla recta
SwainsonpeaSphaerophysa salsula
Tansy ragwortSenecio jacobaea
Wand loosestrifeLythrum virgatum
Water primroseLudwigia hexapetala
White bryonyBryonia alba
Wild carrotDaucus carota
Wild chervilAnthriscus sylvestris
Yellow floating heartNymphoides peltata
Yellow hawkweedHieracium caespitosum