From Oregon Flora, Gardening with Natives:
Pacific ninebark is a medium-sized shrub named for its attractive reddish peeling bark. Small white flowers grow in showy clusters May to June, eventually maturing into clusters of reddish brown capsules. Its 3-lobed leaves provide lovely fall color. An inhabitant of riparian and moist forest habitats, ninebark does well in partial sun and moist soil. Its preference for regular water in summer months makes it ideal as erosion cotrol for the edges of rain and water gardens.