Spiraea roseata Rydberg in N. L. Britton et al., N. Amer. Fl. 22: 250. 1908; S. idahoensis A. Nelson

Leaf abaxial surfaces glabrous or pubescent. Inflorescence branches glabrescent or glabrous. Pedicels glabrescent or glabrous. Flowers: hypanthia and sepals glabrescent or glabrous.

Flowering Jun–Aug; fruiting Jul–Nov. Stream banks, woodland margins, meadows, roadsides; 300–2500 m; Idaho, Wash.

P. A. Rydberg (1917) considered Spiraea roseata to be a hybrid of S. densiflora and S. menziesii (here S. douglasii var. menziesii), and considered S. idahoensis to be a distinct species. At this time, it is unclear whether it is indeed a hybrid or a geographic variant of S. douglasii. The occurrence of specimens in the Columbia River region suggests a hybrid origin.