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WA Invasive Ranking System
The presence and abundance of invasive plants are frequently used in function and condition assessment tools. Existing state lists of noxious weeds and invasive species serve valuable purposes, but incorporate economic impacts and other values that don’t always identify the plant species that are most impactful to the ecology of natural ecosystems. With the assistance of regional experts, Washington Natural Heritage Program staff are working to assemble a consistent, defensible list of the most ecologically impactful invasive plant species in Washington State.
The Washington Invasive Ranking System (WIRS) is a method for assessing the ecological impact of nonnative plant species in natural ecosystems of Washington State. The primary output of WIRS is an Ecological Impact rank, which indicates the degree of ecological degradation caused by a given plant in the ecosystems in which it is found. WIRS also produces supplementary information related to each plant’s management difficulty, biological characteristics, and distribution and abundance.
For complete results for all plants assessed to date, see:
- WIRS Database (Excel)
To access individual species assessments, click on the hyperlinked scientific names in the table below.
Scientific Name | Common Name | Ecological Impact Rank |
---|---|---|
Scientific Name Acer negundo | Common Name Box elder | Ecological Impact Rank Low |
Scientific Name Ailanthus altissima | Common Name tree of Heaven | Ecological Impact Rank Moderate |
Scientific Name Alliaria petiolata | Common Name garlic mustard | Ecological Impact Rank High |
Scientific Name Alopecurus pratensis | Common Name field meadow-foxtail | Ecological Impact Rank Moderate |
Scientific Name Amorpha fruticosa | Common Name Indigobush | Ecological Impact Rank Moderate |
Scientific Name Anthoxanthum odoratum | Common Name sweet vernalgrass | Ecological Impact Rank Moderate |
Scientific Name Arrhenatherum elatius | Common Name tall oatgrass | Ecological Impact Rank Moderate |
Scientific Name Arum italicum ssp. italicum | Common Name Italian arum | Ecological Impact Rank Low |
Scientific Name Arundo donax | Common Name giant reed | Ecological Impact Rank High |
Scientific Name Bellardia viscosa | Common Name Yellow glandweed | Ecological Impact Rank Low |
Scientific Name Bellis perennis | Common Name English daisy | Ecological Impact Rank Insignificant |
Scientific Name Betula pendula | Common Name European white birch | Ecological Impact Rank Low |
Scientific Name Butomus umbellatus | Common Name flowering rush | Ecological Impact Rank High |
Scientific Name Centaurea solstitialis | Common Name yellow star-thistle | Ecological Impact Rank High |
Scientific Name Chondrilla juncea | Common Name rush skeletonweed | Ecological Impact Rank High |
Scientific Name Cirsium arvense | Common Name Canada thistle | Ecological Impact Rank High |
Scientific Name Cirsium vulgare | Common Name bull thistle | Ecological Impact Rank Low |
Scientific Name Clematis vitalba | Common Name old man’s beard | Ecological Impact Rank Moderate |
Scientific Name Cotoneaster spp. | Common Name cotoneaster | Ecological Impact Rank Low |
Scientific Name Crataegus monogyna | Common Name English hawthorn | Ecological Impact Rank High |
Scientific Name Cynoglossum officinale | Common Name houndstongue | Ecological Impact Rank Moderate |
Scientific Name Dianthus armeria | Common Name Deptford pink | Ecological Impact Rank Insignificant |
Scientific Name Dipsacus fullonum | Common Name common teasel | Ecological Impact Rank Moderate |
Scientific Name Erechtites minimus | Common Name toothed coast fireweed | Ecological Impact Rank Low |
Scientific Name Fallopia × bohemica | Common Name Bohemian knotweed | Ecological Impact Rank High |
Scientific Name Hieracium pilosella | Common Name mouse-ear hawkweed | Ecological Impact Rank Low |
Scientific Name Holcus lanatus | Common Name common velvetgrass | Ecological Impact Rank Moderate |
Scientific Name Ilex aquifolium | Common Name English holly | Ecological Impact Rank High |
Scientific Name Impatiens capensis | Common Name spotted jewelweed | Ecological Impact Rank Low |
Scientific Name Iris pseudacorus | Common Name yellow flag iris | Ecological Impact Rank High |
Scientific Name Jacobaea vulgaris | Common Name stinking willie | Ecological Impact Rank Moderate |
Scientific Name Juglans regia | Common Name English walnut | Ecological Impact Rank Low |
Scientific Name Juncus effusus subsp. effusus | Common Name common rush | Ecological Impact Rank Low |
Scientific Name Lamium galeobdolon | Common Name yellow archangel | Ecological Impact Rank Low |
Scientific Name Lathyrus latifolius | Common Name everlasting-pea | Ecological Impact Rank Low |
Scientific Name Lathyrus sylvestris | Common Name narrow-leaf pea | Ecological Impact Rank Low |
Scientific Name Leucanthemum vulgare | Common Name oxeye daisy | Ecological Impact Rank Moderate |
Scientific Name Lysimachia nummularia | Common Name garden loosestrife | Ecological Impact Rank Low |
Scientific Name Lythrum salicaria | Common Name purple loosestrife | Ecological Impact Rank Moderate |
Scientific Name Marrubium vulgare | Common Name white horehound | Ecological Impact Rank Insignificant |
Scientific Name Mycelis muralis | Common Name wall lettuce | Ecological Impact Rank Insignificant |
Scientific Name Myosotis discolor | Common Name yellow and blue scorpiongrass | Ecological Impact Rank Insignificant |
Scientific Name Myriophyllum heterophyllum | Common Name variable-leaf milfoil | Ecological Impact Rank High |
Scientific Name Myriophyllum spicatum | Common Name Eurasian watermilfoil | Ecological Impact Rank High |
Scientific Name Nasturtium officinale | Common Name watercress | Ecological Impact Rank Moderate |
Scientific Name Phalaris arundinacea | Common Name reed canarygrass | Ecological Impact Rank High |
Scientific Name Phleum pratense | Common Name Timothy | Ecological Impact Rank Low |
Scientific Name Plantago lanceolata | Common Name English plantain | Ecological Impact Rank Insignificant |
Scientific Name Poa annua | Common Name annual bluegrass | Ecological Impact Rank Insignificant |
Scientific Name Potamogeton crispus | Common Name curlyleaf pondweed | Ecological Impact Rank High |
Scientific Name Quercus robur | Common Name English oak | Ecological Impact Rank Low |
Scientific Name Rosa canina | Common Name dog rose | Ecological Impact Rank Moderate |
Scientific Name Rosa multiflora | Common Name multiflora rose | Ecological Impact Rank Moderate |
Scientific Name Rosa rugosa | Common Name rugosa rose | Ecological Impact Rank Low |
Scientific Name Rubus bifrons | Common Name Himalayan blackberry | Ecological Impact Rank High |
Scientific Name Rubus laciniatus | Common Name cut-leaf blackberry | Ecological Impact Rank Moderate |
Scientific Name Rumex crispus | Common Name curly dock | Ecological Impact Rank Insignificant |
Scientific Name Sasa palmata | Common Name broadleaf bamboo | Ecological Impact Rank Moderate |
Scientific Name Schedonorus arundinaceus | Common Name tall fescue | Ecological Impact Rank Moderate |
Scientific Name Schoenoplectus mucronatus | Common Name ricefield bullrush | Ecological Impact Rank Low |
Scientific Name Senecio sylvaticus | Common Name woodland groundsel | Ecological Impact Rank Insignificant |
Scientific Name Solanum dulcamara | Common Name bittersweet nightshade | Ecological Impact Rank Low |
Scientific Name Solidago altissima | Common Name late goldenrod | Ecological Impact Rank Moderate |
Scientific Name Spartina alterniflora | Common Name smooth cordgrass | Ecological Impact Rank High |
Scientific Name Tamarix ramosissima | Common Name saltcedar | Ecological Impact Rank High |
Scientific Name Trifolium pratense | Common Name red clover | Ecological Impact Rank Low |
Scientific Name Trifolium subterraneum | Common Name burrowing clover | Ecological Impact Rank Low |
Scientific Name Utricularia inflata | Common Name wwollen bladderwort | Ecological Impact Rank High |
Scientific Name Verbascum blattaria | Common Name moth mullein | Ecological Impact Rank Insignificant |
Scientific Name Veronica anagallis-aquatica | Common Name water speedwell | Ecological Impact Rank Insignificant |
Scientific Name Veronica arvensis | Common Name wall speedwell | Ecological Impact Rank Insignificant |