We Join the Battle Against Indigobush in the Columbia River Gorge

Sometimes invasive species get so out of control, only a large-scale coordinated attack will eliminate them. Such is the case with indigobush (Amorpha fruticosa) in the Columbia River Gorge. Originally planted as an ornamental, this bush has taken over many miles of shoreline in the Gorge—and that’s not good.

Indigobush forms dense thickets along rivers and streams, displaces native plants, and degrades shoreline spawning areas for salmon and other fish. So when Skamania County created the Cooperative Indigobush Control Project, we gladly joined the frontline troops. Our collective goal is to eradicate the invader from the Columbia River Gorge.

Columbia Land Trust’s stewardship team is doing its part by eliminating indigobush on Pierce Island, which sits directly below Beacon Rock. This summer will be Year Two for our Pierce Island indigobush battle. (As even the home gardener knows, it often takes a multi-year effort to get rid of particularly stubborn weeds.) Eliminating indigobush from Pierce will be good for the state-endangered Columbia yellow cress (Rorippa columbiae), a diminutive plant with yellow flowers that grows only on Pierce Island and in one other place in Washington State. Other partners waging the indigobush battle in the Gorge include the U.S. Fish and Wildlife Service, Washington State Parks, the USDA Forest Service, and the U.S. Army Corp of Engineers. —Dan Friesz