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King County, Washington noxious weed identification and control

Phragmites
Phragmites australis

phragmites infestationThis tall wetland grass is also known as common reed. There are both native and non-native strains of this plant in Washington. Due to its aggressive tendencies and impact to waterways, the non-native strain or haplotype is a Phragmites found in both eastern and western Washington and some infestations are many acres in size. In King County, most infestations are still small and can be eradicated. Because native populations have been found in the region, careful identification by an expert is needed before any eradication measures are taken.

The Washington State Department of Agriculture (WSDA) received a grant from Department of Ecology in 2003 to undertake a statewide phragmites project. The project began mapping all known locations of phragmites using GPS technology and to develop a GIS layer for the State. The researchers submitted samples from each site to Dr. Bernd Blossey at Cornell University for genotyping and input into his national database. All of the populations from King County were identified as the non-native haplotype. For more information on this project and how to distinguish the types of phragmites, check out Cornell University's website.

Legal status in King County, Washington

Class B designate weed in Washington State. Because of the limited distribution in the county and the potential serious impact, control of phragmites is required in King County.

Additional information on phragmites

Phragmites photos - click thumbnail for larger image

phragmites stalk - click for larger image phragmites infest - click for larger image phragmites infest - click for larger image

Report phragmites in King County, Washington

Locate phragmites in King County, Washington

Related information

Related 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.