Description from Flora of China
Hydrangea bretschneideri Dippel var. giraldii (Diels) Rehder; H. giraldii Diels; H. hypoglauca var. giraldii (Diels) C. F. Wei; H. hypoglauca var. obovata Chun.
Shrubs 1-3 m tall. Branchlets red-brown, glabrous or sparsely shortly and thickly hairy when young; bark peeled off into fragments when old. Petiole thin, 1.5-3 cm; leaf blade abaxially gray-white, ovate or oblong-ovate or oblong-obovate, 7-12 × 2.8-6.5 cm, papery, abaxially densely glandular granular and roughly long hairy, glabrous, or subglabrous except pubescent along veins, adaxially glabrous or sparsely appressed shortly and thickly hairy along veins, secondary veins 7 or 8 on both sides of midvein, erect and obliquely ascending, abaxially elevated, base rounded to subacute, margin serrulate, apex acuminate. Inflorescences corymbose cymes, 10-14 cm wide, apex slightly arcuate; branches 3, sparsely appressed long hairy. Sterile flowers with sepals 3 or 4, white, obovate, broadly ovate, or broadly orbicular, ca. 1.1 × 2 cm. Fertile flowers with calyx tube campanulate, ca. 1 mm; teeth ovate-triangular, 0.5-1 mm. Petals white, oblong-ovate, 2-2.5 mm. Stamens unequal, longer ones inflexed in bud, ca. 3 mm; anthers subglobose, less than 0.5 mm. Ovary up to 1/2 superior. Styles 3, basally connate, subulate or not, 1-1.5 mm; stigmas not enlarged to subcapitate. Capsule ovoid-globose, ca. 3 mm in diam., projected apical part conical, ca. 1.5 mm, subequaling calyx tube. Seeds brownish, fusiform, winged at both ends; wings 0.5-0.7 mm; seed coat striate veined. Fl. Jun-Jul, fr. Sep-Oct.
* Dense to sparse forests on mountain slopes or tops, thickets in valleys or on mountain slopes; 200-4000 m. NE Guizhou, W Hubei, NW Hunan, SW Shaanxi, E Sichuan, NW Yunnan.