Description from Flora of China
Hydrangea aspera D. Don var. angustifolia Hemsley; H. aspera var. macrophylla Hemsley; H. aspera var. sinica Diels; H. aspera subsp. strigosa (Rehder) E. M. McClintock; H. strigosa var. angustifolia (Hemsley) Rehder; H. strigosa var. macrophylla (Hemsley) Rehder; H. strigosa var. purpurea C. C. Yang; H. strigosa var. sinica (Diels) Rehder; H. strigosa f. sterilis Rehder.
Shrubs 1-3 m tall. Branchlets gray-brown, terete or obscurely 4-angled, densely strigose; bark usually peeled off into fragments. Petiole 1-7 cm, strigose; leaf blade abaxially sometimes purplish red to reddish when fresh but gray-brown to gray-green when dry, adaxially black-brown, oblong, ovate-lanceolate, or obovate-oblanceolate, 8-28 × 2-10 cm, papery, abaxially densely gray-brown glandular granular and gray-white strigose, adaxially sparsely strigose to subglabrous, secondary veins 7-10 on both sides of midvein, abaxially prominent, base obtuse, cuneate, or rounded, margin serrulate, apex acuminate. Inflorescences corymbose cymes, to 28 cm wide, apex slightly arcuate; branches spreading, gray-white strigose. Sterile flowers with sepals 4 or 5, white to purplish red, broadly ovate, broadly elliptic, suborbicular, or broadly orbicular, margin entire to denticulate. Fertile flowers with calyx tube campanulate, ca. 2 mm; teeth triangular, ca. 0.5 mm. Petals purplish red, oblong-ovate, 2-2.5 mm. Stamens 10, unequal, 3-6 mm; anthers oblong, ca. 0.5 mm. Ovary inferior. Styles 2, erect to recurved, slightly clavate, ca. 2 mm in fruit. Capsule urn-shaped, 3-3.5 mm in diam., apex truncate. Seeds brown, broadly ellipsoid, 0.3-0.5 mm, winged at both ends; wings 0.2-0.3 mm; seed coat striate veined. Fl. Jul-Aug, fr. Oct-Dec.
* Dense to sparse forests or thickets in valleys, trailsides on mountain slopes; 500-1800 m. NW Guizhou, W Hubei, NW Hunan, S Shaanxi, Sichuan.