Washington State Noxious Weed Control Board
Washington State Noxious Weed Monitor List
The purpose of the “monitor list” is to gather more information on suspect weeds, as well as monitor for occurrence or spread. Information collected from weeds on the monitor list may be used to justify future inclusion on the state noxious weed list. There is no legal or regulatory aspect to this list (WAC 16-750-025).
Species listed on the Washington State Monitor List are being monitored because:
- They are new invaders to Washington and have the potential to become problematic here.
- They are non-native species that have been here awhile and behaving fine but have suddenly started to spread or become problematic.
- They have recently been removed from the Weed List but we want to stay on the lookout to make sure the noxious weeds do not make a return invasion.
We need your help to learn more about the species on the monitor list. If you find plant species on the monitor list, please report your finding to the relevant sponsor listed with each species. Please include such information as site location, size of distribution, habitat, etc. when making your report.
| Bladderwort, swollen Utricularia inflata Sponsor: Jenifer Parsons | Blooddrops Adonis annua Sponsor: Nelle Murray | Bursage, skeletonleaf Ambrosia tomentosa Sponsor: Vacant | Catchfly, Balkan Typha angustifolia Sponsor: Jenifer Parsons | Celandine, lesser Ficaria verna Sponsor: Laurel Baldwin |
| Cinquefoil, silvery Potentilla argentea Sponsor: D. Gaiser | Clematis, Chinese Clematis orientalis Sponsor: Dick Jacobsen | Crosswort, narrowleaved Crucianella angustifolia Sponsor: Vacant | Fieldcress, creeping Rorippa sylvestris Sponsor: P. Stevenson | Flowering rush Butomus umbellatus Sponsor: Laurel Baldwin |
| Frogs-bit, Eurasian Hydrocharis morsus-ranae Sponsor: Alison Halpern | Giant Reed Arundo donax Sponsor: Steven Link | Green alkanet Pentaglottis sempervirens Sponsor: Danielle Warner | Inula Inula helenium Sponsor: Sue Winterowd | Knapweed, featherhead Centaurea tricocephala Sponsor: Dick Jacobson |
| Mallow, venice Hibiscus trionum Sponsor: Bridget Simon | Pampas grass Cortaderia spp. Sponsor: Rick Johnson | Evening Primrose? | Sedge, lovegrass Cyperus eragrostis Sponsor: Jim Comrada | Teasel, common Dipsacus fullonum Sponsor: Bill Rogers |
| Thistle, distaff Carthamus lanatus Sponsor: Bill Wamsley | Unicorn-plant Proboscidea louisianica Sponsor: Sharon Sorby | Verbena, tall Verbena bonariensis Sponsor: Sarah Reichard | Vine, silverlace Polygonum albertii Sponsor: King county | Watercress Rorippa nasturtium-aquaticum Sponsor: Cathy Lucero |
| Waterhyacinth Eichhornia crassipes Sponsor: Kathy Hamel |