Spiraea lucida

About

Spiraea lucida, the shiny-leaf meadowsweet, is a species of flowering plant in the family Rosaceae, native to western Canada as far as Saskatchewan, and the northwestern United States as far as the Dakotas. In the past, due to its leaf morphology varying greatly because of the plants' tendency to die back to the ground in winter, it was considered a variety of Spiraea betulifolia, the white or birch-leaf meadowsweet.

Summary from Wikipedia