Description from Flora of China
Shrubs erect, to 1.5 m tall. Branchlets brownish to purple-brown, slender, subterete, glabrous or pubescent when young; buds ovoid, 3–5 mm, with several scales, puberulous, apex acute. Petiole 1–3 mm, pubescent; leaf blade abaxially paler or glaucous pruinose, adaxially dark green, ovate or ovate-elliptic to lanceolate or oblong-lanceolate, 2–16 × 1–4 cm, abaxially usually pubescent on veins, adaxially glabrous or puberulous on veins, base cuneate to rounded, margin crenate to doubly serrate, rarely singly serrate, apex obtuse or acute to acuminate. Corymbs terminal on erect, long, leafy shoots of current year, compound, 6–14 × 2.5–14 cm, many flowered; rachis and pedicels densely pubescent; pedicels 4–6 mm; bracts lanceolate to linear-lanceolate, sometimes to 1 cm, abaxially puberulous. Flowers 4–7 mm. Hypanthium campanulate, sparsely pubescent abaxially. Sepals triangular, 1.5–2 mm, erect in fruit, apex acute. Petals usually pink, sometimes white, ovate to orbicular, 2.5–3.5 × 2–3 mm, apex obtuse. Stamens 25–30, much longer than petals. Disk annular, irregularly crenulate. Follicles divergent, glabrous or pilose on adaxial suture; styles ascending. Fl. Jun–Jul, fr. Aug–Sep.
Eight varieties may be recognized in China. In addition, Spiraea japonica var. stellaris Rehder (in Sargent, Pl. Wilson. 1: 452. 1913) was described on the basis of a fruiting specimen (A. Henry 9280) from SE Yunnan (Mengzi Xian).
Forests, forested slopes, forest clearings, thickets, grassy slopes, mountain valleys, gullies, river banks, alpine steppes, rocky and stony places also commonly cultivated; 700--4000 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Sichuan, Xizang, Yunnan, Zhejiang [Japan, Korea].