Pacific Ninebark (Physocarpus capitatus), also known Physocarpus opulifolius (L.) Maxim. var. tomentellus (Ser.) Boivin and Spiraea capitatus Kursh. It grows in riparian and coastal areas. It is not very common in Idaho and only grows in the Clearwater and Snake River drainages. It provides good cover and nesting for birds and small mammals but is not very palatable for browsing. The reddish, papery bark peels off in long layers. Leaves are alternate along the stem, 3-10 cm long, 3-5 lobes and doubly toothed at the margin. They are shiny dark green above and lighter beneath with fine, star-shaped hairs and deeply veined. Fun fact, capitatus stands for headlike flower clusters.
Height: 6' to 12'
Solar Exposure: Prefers part-shade, tolerates full-sun
Bloom Color: Creamy-white with pink stamens
Bloom Time: April through July
USDA PLANTS Database Link