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Reed canarygrass identification and control: Phalaris arundinacea

Reed canarygrass identification and control

Phalaris arundinacea


Reed canarygrass, a non-regulated Class C noxious weed, is a 3-9-foot-tall perennial grass commonly found in wetlands, ditches, damp pastures, and on shorelines. Bright green, flat, rough leaves grow at a 45-degree angle from hairless stems. Flower heads appear in narrow clusters high above leaves. This plant grows primarily from mid-June to mid-August, reproducing both by seed and vegetatively via rhizomes. It chokes out streams and ditches, increasing flooding and impeding salmon and other fish. Although used at times for forage in pastures, it can cause indigestion and illness in livestock.


Reed 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

reed canary grass

This Class C noxious weed is widespread in Washington and control in King County is not required. Control is recommended where possible, especially in restoration projects where wetland functions are being restored. For more information about noxious weed regulations and definitions, see Noxious weed lists and laws.

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).