Description from Flora of China
Hydrangea aspera f. emasculata Chun; H. aspera var. strigosior Diels; H. aspera var. velutina Rehder; H. glabripes Rehder; H. villosa Rehder; H. villosa var. delicatula Chun; H. villosa f. sterilis Rehder; H. villosa var. strigosior (Diels) Rehder; H. villosa var. velutina (Rehder) Chun.
Shrubs or small trees, 1-4(-10) m tall. Branchlets terete or obscurely 4-angled, densely yellow- to gray-white shortly strigose, pubescent, and villous; bark brown. Petiole 1-4.5 cm, densely strigose or glabrous; leaf blade lanceolate, ovate-lanceolate, ovate-oblong, ovate, or elliptic-oblong, 5-25 × 2-8 cm, papery, abaxially densely gray-white pubescent to long villous, adaxially sparsely to densely strigose, secondary veins 6-10 on both sides of midvein, base broadly cuneate to rounded, margin serrate to doubly so, apex long acuminate. Inflorescences corymbose cymes, 8-25 cm wide, apex arcuate; branches densely gray-yellow pubescent. Sterile flowers with sepals 4 or 5, greenish white, pinkish, or red, broadly ovate, obovate-orbicular, or orbicular, 1-3.3 × 0.9-2.7 cm, margin acutely dentate, crenulate, or entire. Fertile flowers with calyx tube campanulate to cupular, 1-1.5 mm; teeth broadly triangular to ovate-triangular, 0.5-1 mm. Petals purple-blue or purple-red, oblong-ovate to ovate, 1.5-2.5 mm, base truncate. Stamens 10, unequal; anthers subglobose, ca. 0.5 mm. Ovary inferior. Styles 2 or 3, recurved, ca. 1-2 mm in fruit; stigmas slightly enlarged. Capsule urn-shaped, 3-3.5 mm in diam., base subacute, apex truncate. Seeds brown, fusiform, ellipsoid, or subglobose, slightly compressed, 0.4-0.5 mm, winged at both ends; wings ca. 0.2 mm; seed coat striate veined. Fl. Jul-Sep, fr. Sep-Nov.
Dense forests or thickets in valleys or on mountain slopes; 700-4000 m. SE Gansu, Guangxi, Guizhou, SW Hubei, SW Hunan, Jiangsu, Shaanxi, Sichuan, Yunnan [NE India, Nepal, Sikkim, Vietnam].