Washington State continues quest to eradicate invasive Spartina

OLYMPIA – This year’s treatment season for Spartina, an aggressive invasive weed, starts June 1 and will continue through November.

Survey and eradication efforts for Spartina, led by the Washington State Department of Agriculture (WSDA), will take place in multiple areas, including Grays Harbor, Hood Canal, Willapa Bay, Puget Sound, the north and west sides of the Olympic Peninsula and near the mouth of the Columbia River.

This year’s efforts build on the work completed last season when thorough surveys detected recently established Spartina within restored wetlands in the North Puget Sound. The project partners will work to stop the trend of Spartina spreading into and impacting important restoration projects. Since 1995, WSDA has served as the lead state agency for Spartina eradication, facilitating the cooperation of local, state, federal and tribal governments; universities; interested groups; and private landowners. The cooperative effort located and treated over 17,000 individual Spartina plants last year.

The Spartina eradication effort has been highly effective – reducing infestations from a high of more than 9,000 solid acres in 2003 to just over four total acres in 2023.

The effort has successfully eradicated Spartina at 75 sites, however significant work remains to be done. The four remaining acres are spread over 126 sites - meaning 62 percent of Washington’s known infestations are not yet eradicated.

“Our goal is to eradicate Washington’s remaining Spartina infestations, protecting important habitat for salmon, waterfowl and shellfish,” said Chad Phillips, WSDA’s Spartina Program Coordinator. “The Spartina Eradication Program protects our state’s most productive estuaries and shoreline habitats. This year, with our project cooperators, we will continue the challenging work of finding and removing the thousands of Spartina plants that remain in the Puget Sound and along Washington’s coast.”

This season, project partners will survey thousands of acres of saltwater estuaries and hundreds of miles of shoreline. WSDA and its partners typically dig out small infestations by hand and utilize herbicides at larger sites.

Spartina, commonly known as cordgrass, can disrupt the ecosystems of native saltwater estuaries. If left unchecked, Spartina outcompetes native vegetation and converts ecologically healthy mudflats and estuaries into solid Spartina meadows. As a result, important habitat for salmon, forage fish, invertebrates, shorebirds and waterfowl are lost, the threat of flooding is increased, and the state’s shellfish industry is negatively impacted.

Visit agr.wa.gov to for more information on Spartina control efforts.