Description from Flora of China
Shrubs climbing. Young branchlets, petioles, and inflorescences densely yellow-brown pubescent. Branchlets dark gray, terete, glabrescent. Petiole 2-9 cm; leaf blade oblong-ovate to elliptic, 9-12 × 4.5-10 cm, papery, abaxially densely slightly crisped pubescent, adaxially sparsely strigose, secondary veins 6 or 7 on both sides of midvein, abaxially prominent, base broadly cuneate to rounded, margin irregularly doubly serrate, apex acute to shortly acuminate. Inflorescences corymbose cymes, lax, 10-14 cm wide, apex truncate to slightly arcuate. Sterile flowers with sepals 3 or 4, suborbicular, 1-2 cm, margin acutely dentate. Fertile flowers with calyx tube cupular, ca. 1.5 mm; teeth broadly triangular, ca. 1 mm. Petals oblong-ovate, ca. 2 mm. Stamens 10, unequal, longer ones ca. 5 mm; anthers subglobose, ca. 0.5 mm. Ovary inferior. Styles 2(or 3), ca. 1.5 mm in fruit. Capsule hemispheric, 2-3 × 3-4 mm, apex truncate. Seeds fusiform, shortly winged at both ends; seed coat striate veined with thin, transverse veins in-between. Fl. Jul, fr. Oct-Nov.
One of the present authors (Bartholomew) believes that this species is not distinct from Hydrangea aspera.
* Dense forests; 2200-2300 m. Taiwan.