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King County, Washington Noxious Weed Identification and Control

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Noxious Weed List

Class A Noxious Weeds, 2008 List
(eradication required throughout Washington State including King County)

Common Name Scientific Name
bighead knapweed Centaurea macrocephala
buffalobur Solanum rostratum
clary sage Salvia sclarea
common cordgrass Spartina anglica
common crupina Crupina vulgaris
dense flower cordgrass Spartina densiflora
dyers woad Isatis tinctoria
eggleaf spurge Euphorbia oblongata
European hawkweed Hieracium sabaudum
floating primrose-willow Ludwigia peploides
garlic mustard Alliaria petiolata
giant hogweed Heracleum mantegazzianum
goatsrue Galega officinalis
hydrilla Hydrilla verticillata
Italian thistle Carduus pycnocephalus
johnsongrass Sorghum halepense
kudzu Pueraria montana var. lobata
meadow clary Salvia pratensis
Mediterranean sage Salvia aethiopis
milk thistle Silybum marianum
purple starthistle Centaurea calcitrapa
reed sweetgrass Glyceria maxima
ricefield bulrush Schoenoplectus mucronatus
salt meadow cordgrass Spartina patens
silverleaf nightshade Solanum elaeagnifolium
slenderflower thistle Carduus tenuiflorus
Spanish broom Spartium junceum
spurge flax Thymelaea passerina
Syrian bean-caper Zygophyllum fabago
Texas blueweed Helianthus ciliaris
variable-leaf milfoil Myriophyllum heterophyllum
velvetleaf Abutilon theophrasti
Vochin knapweed Centaurea nigrescens
yellow devil hawkweed Hieracium floribundum

Class B Weeds 2008 list
(control required in King County)

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

Class C Noxious Weeds 2008 list
(control required in King County)

Common Name Scientific Name
common hawkweed Hieracium lachenalii
hairy willowherb Epilobium hirsutum
non-native and invasive hawkweeds Hieracium spp.

Non-designated Noxious Weeds 2008 list
(non-designate B and C weeds, control recommended but not required in King County)

Common Name Scientific Name
absinth wormwood Artemisia absinthium
Atlantic ivy Hedera hibernica
Bohemian knotweed Polygonum bohemicum
bull thistle Cirsium vulgare Cirsium vulgare
butterfly bush Buddleia davidii
Canada thistle Cirsium arvense
common fennel (except bulbing variety azoricum) Foeniculum vulgare
common groundsel Senecio vulgaris
common St. Johnswort Hypericum perforatum
common tansy Tanacetum vulgare
curly-leaf pondweed Potamogeton crispus
English ivy Hedera helix Baltica
English ivy Hedera helix Pittsburgh
English ivy Hedera helix Star
Eurasian watermilfoil Myriophyllum spicatum
field bindweed Convolvulus arvensis
fragrant water lily Nymphaea odorata
giant knotweed Polygonum sachalinense
herb Robert Geranium robertianum
Himalayan knotweed Polygonum polystachyum
Japanese knotweed Polygonum cuspidatum
lawnweed Soliva sessilis
myrtle spurge Euphorbia myrsinites
old man's beard Clematis vitalba
oxeye daisy Leucanthemum vulgare
poison-hemlock Conium maculatum
reed canarygrass Phalaris arundinacea
Scotch broom (required SR-2, I-90 E. of MP 34) Cytisus scoparius
spurge laurel Daphne laureola
wild carrot Daucus carota
yellow archangel Lamiastrum galeobdolon
yellow flag iris Iris pseudacorus
yellow toadflax Linaria vulgaris

Noxious Weeds of Concern 2008 list
(unregulated weeds that nonetheless often impact and degrade native plant and animal habitat)

Common Name Scientific Name
bittersweet nightshade Solanum dulcamara
creeping buttercup Ranunculus repens
English holly Ilex aquifolium
English laurel Prunus laurocerasus
evergreen blackberry Rubus laciniatus
Hedge Bindweed Calystegia sepium
Himalayan blackberry Rubus armeniacus
tall buttercup Ranunculus acris

 

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Agencies

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.