State continues quest to eradicate invasive Spartina

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

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

Since 1995, WSDA has served as the lead state agency for Spartina eradication, a cooperative effort involving local, state, federal and tribal governments; universities; interested groups and private landowners. Together, this partnership identified and treated over 29,000 individual Spartina plants last year.

Recently, Spartina has invaded valuable salmon restoration sites in the North Puget Sound. A significant goal of the 2026 effort will be to address the Spartina spread into these sites and find eradication solutions.

The Spartina eradication effort has been highly effective — reducing infestations from a high of more than 9,000 solid acres in 2003 to 6.4 solid acres in 2025.

The effort has successfully eradicated Spartina at 80 sites; however, significant work remains. The remaining plants are spread over 122 sites — meaning 60 percent of Washington’s 202 infested sites are not yet eradicated.

“Our goal is to eradicate Washington’s remaining Spartina infestations, protecting important habitat for salmon, waterfowl and shellfish,” Chad Phillips, WSDA’s Spartina Program Coordinator, said. “The Spartina Eradication Program protects our state’s most productive estuaries and shoreline habitats. This year, with our project partners, 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, the 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 infestations.

Eradication is vital to protect Washington’s valuable restoration projects, shorelines, and ecosystems

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 monocultures. 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.