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Class B Noxious Weeds, 2009 List
(control required in King County)

Scientific Name Common Name
Acroptilon repens Russian knapweed
Alhagi maurorum camelthorn
Alopecurus myosuroides blackgrass
Anchusa arvensis annual bugloss
Anchusa officinalis common bugloss
Anthriscus sylvestris wild chervil
Berteroa incana hoary alyssum
Bryonia alba white bryony
Cabomba caroliniana fanwort
Carduus nutans musk thistle
Carduus acanthoides plumeless thistle
Cenchrus longispinus longspine sandbur
Centaurea solstitialis yellow starthistle
Centaurea biebersteinii spotted knapweed
Centaurea nigra black knapweed
Centaurea jacea brown knapweed
Centaurea diffusa diffuse knapweed
Centaurea jacea x nigra meadow knapweed
Chondrilla juncea rush skeletonweed
Cyperus esculentus yellow nutsedge
Echium vulgare blueweed, viper's bugloss
Egeria densa* Brazilian elodea
Euphorbia esula leafy spurge
Hieracium pilosella mouseear hawkweed
Hieracium aurantiacum orange hawkweed
Hieracium atratum polar hawkweed
Hieracium glomeratum queen-devil hawkweed
Hieracium laevigatum smooth hawkweed
Hieracium caespitosum  yellow hawkweed
Impatiens glandulifera policeman's helmet
Kochia scoparia kochia
Lepidium latifolium perennial pepperweed
Lepyrodiclis holosteoides lepyrodiclis
Linaria dalmatica ssp. dalmatica  Dalmatian toadflax
Ludwigia hexapetala water primrose
Lysimachia vulgaris garden loosestrife
Lythrum salicaria purple loosestrife
Myriophyllum aquaticum parrotfeather
Nymphoides peltata yellow floating heart
Onopordum acanthium Scotch thistle
Phragmites australis common reed (non-native genotypes)
Picris hieracioides oxtongue hawkweed
Potentilla recta sulfur cinquefoil
Rorippa austriaca Austrian fieldcress
Sagittaria graminea grass-leaved arrowhead
Senecio jacobaea tansy ragwort
Sonchus arvensis perennial sowthistle
Spartina alterniflora smooth cordgrass
Sphaerophysa salsula swainsonpea
Tamarix ramosissima Tamarix ramosissima saltcedar
Ulex europaeus gorse
*Brazilian elodea is designated for control throughout King County except in Lake Washington, Lake Sammamish, Lake Union and Lake Fenwick.

King County Noxious Weed List

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Program offices are located at 201 S. Jackson St., Suite 600, Seattle, WA 98104. To contact a staff member at the King County Noxious Weed Control Program, please call 206-296-0290 or by reach them by email.