Hydrangea schizomollis Y.De Smet & Granados

A climber, new, rare and rather tentatively identified in Western gardens, H. schizomollis is one of the strikingly similar, taxonomically difficult species in Section Schizophragma (see the more widely grown H. ampla and H. hydrangeoides). Schizophragmas share a climbing habit, deciduous foliage, a summer flowering period, enlarged fertile flowers with free petals, and a single (rarely 2–3) sepal per sterile flower. This widespread central Chinese species, extending south into Vietnam (Lecompte 1965), has untoothed leaves densely tomentose across the underside, not only adjacent to the veins (Liu & Zhu 2011). It is most similar to the Taiwanese endemic H. fauriei, and still better known as Schizophragma molle. Like other schizophragmas it is likely to succeed on shady to sunny walls, trees and other structures, flowering best with summer warmth and good light levels.

This plant was first described scientifically (as Schizophragma integrifolium var. molle, referring to the hairy leaf undersurface) from herbarium specimens collected on Wa Shan, Sichuan. by Ernest Wilson in 1908 (Sargent 1913). There is no suggestion that Wilson collected seed. Later raised to a full species, a completely new epithet was required on transfer to Hydrangea because the name H. mollis (Rehder) W.T.Wang had already been used for a plant in the orbit of H. heteromalla (De Smet et al. 2015).

Oddly, we have not traced any introductions from its Chinese heartland, but three collections from N Vietnam seem to belong here. Dan Hinkley’s DJHV 8170 has had a limited commercial distribution in North America; he describes its ‘felted grayish green’ foliage and ‘large creamy heads’ (Hinkley 2023). There are also two Crûg Farm collections, HWJ 1011 and WWJ 11905. The latter has proved hardy on a south-facing wall in North Wales, UK and is available commercially. At one time listed as S. elliptifolium (a synonym of H. glaucescens), both seem a better fit for H. schizomollis, although the entire upper leaf surface is covered with soft, somewhat appressed hairs; some inflorescences lack showy sepals on the sterile flowers (Shaw 2012; Crûg Farm Plants 2023).