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Noxious weeds

King County, Washington

To offer a suggestion or report an error on the King County Noxious Weeds website, please contact Sasha Shaw, education specialist.

Reed canarygrass
Phalaris arundinacea

reed canary grassReed canarygrass is a tall wetland grass that forms dense, single-species stands. It chokes out streams and ditches increasing flooding and impeding salmon and other fish. Although used at times for forage in wet pastures, it can cause indigestion and illness in livestock.

Reed canarygrass flower stalkReed canarygrass grows 3 to 6 feet tall and has sturdy hollow stems up to ½ inch wide, with reddish coloring near the top. The leaf blades are flat, hairless, wide, and come off the stem at a 45 degree angle. Flower spikes are large and compact on stems high above the leaves in June and July.

This aggressive grass poses many challenges to management and creates significant problems for restoration projects. It spreads by rhizomes, fragments and seeds. The dense rhizomatous mats exclude other roots and make removal highly difficult. Stems fall and form mounds by the end of summer, further inhibiting native wetland species from re-colonizing infested areas.

Legal status in King County, Washington

This Class C weed is widespread in Washington State and control in King County is not required, but strongly recommended where possible, especially in restoration projects where wetland functions are being restored. Reed canarygrass is not on the quarantine list administered by the Washington State Department of Agriculture, but some nurseries have volunteered to stop selling it due to its danger to natural resources.

Additional information on reed canarygrass

What to do if you find this plant in King County, Washington

Because reed canarygrass is so widespread, property owners in King County are not required to control it and we are not generally tracking infestations. We can provide advice on how to control reed canarygrass, but there is generally no legal requirement to do so.

The King County Noxious Weed Control Board encourages property owners to remove reed canarygrass where possible and to avoid introducing it to new landscapes.

Report reed canarygrass in King County, Washington

Locate reed canarygrass in King County, Washington

Related information

Related agencies


Program offices are located at 201 S. Jackson St., Suite 600, Seattle, WA 98104. To contact staff, see the Noxious Weed Control Program Directory, send an email, or call 206-477-WEED (206-477-9333).