China, Korea, Japan
"Spiraea japonica, commonly called Japanese spirea, is a dense, upright, mounded, deciduous shrub that typically grows 4-6’ tall with a slightly larger spread. Leaves (to 3” long) are oval and sharply-toothed. Tiny pink flowers in flat-topped clusters (corymbs) cover the foliage from late spring to mid-summer, with sparse and intermittent repeat bloom sometimes occurring. Flowers are attractive to butterflies." (MOBOT)