Hydrangea daimingshanensis (Y.C.Wu) Y.De Smet & Granados

A member of Section Dichroa, the Chinese botanical consensus is that H. daimingshanensis is distinct from the much more widespread, very variable H. febrifuga (see that species for general discussion of dichroas). In cultivation, things seem less clear cut. A few collections approximate to it and are sometimes labelled H. daimingshanensis, sometimes H. febrifuga. These are evergreen to semi-evergreen, depending on conditions, and not very hardy; they have blue / pink to whitish fertile flowers and blue berries.

The description above is taken from Flora of China (Huang & Bartholomew 2001), largely based on Hwang (1987). Key identification features include indumentum and calyx lobes. H. daimingshanensis has a mixture of two hair types on the veins, petioles and young branchlets, some short and crisped, others long, straight and spreading. The halo of spreading hairs around the branchlets is unmistakeable in images of herbarium specimens (the type included) from the early to mid 20th century, the material which would have been studied when describing it (Chinese Academy of Sciences 2024). Calyx lobes in H. daimingshanensis are glabrous, short and deltoid rather than lanceolate. Almost every specimen identified as such is from either Guangxi or Guizhou; many are from forest, others from more open, exposed areas.

At least two collections in Western gardens have been placed here, one quite widely established. GUIZ 48 was collected as Dichroa sp. in Guizhou, on a track edge in full sun at 770 m asl, in 1985, the parent plant being only 60–70 cm tall. It has thick-textured, more or less elliptic leaves, quite coarsely and sharply toothed, the apex sometimes abruptly acuminate; indumentum approximates to the description above (pers. obs. at Crûg Farm, UK, August 2023). It has gained a modest distribution in Britain, rather more so in North America. It generally remains no more than 1 m tall, with whitish buds opening blue to pinkish, with darker stamens, in summer and autumn (Pan-Global Plants 2024) and seems reasonably hardy in southern England (Exclusive Plants 2024). Following herbarium work, GUIZ 48 was identified as H. daimingshanensis by Shaw 2014); at the very least, it seems the best candidate for the species we have in gardens. There is a low-growing specimen in the Temperate House at RBG Kew (pers. obs. 2025). The plant grown in North America as “H. febrifuga UBC clone” is in fact GUIZ 48 and not as usually suggested a Peter Wharton collection. It was received as a plant in 1988 by Wharton at University of British Columbia Botanical Garden, from Jim Russell, UK, a member of the GUIZ collecting team (UBC BG catalogue – A. Lopez Villalobos pers. comm. 2025). It is a hexaploid and – awkwardly as a candidate for H. daimingshanensis – something of a benchmark for H. febrifuga in a molecular analysis of dichroas and their hybrids (Rinehart, Scheffler & Reed 2010).

More recent and scarcely tested, but again tentatively placed in H. daimingshanensis, is Crûg Farm’s BWJ 15621 (NE Vietnam 2017), collected on a rocky, exposed roadside, the parent around 1 m tall with blue stems and bluish young growth. In cultivation has much thinner textured and less rounded leaves than the previous collection, ovate to elliptic, and tapering at both ends, sometimes acuminate, without much blue in the shoots (Crûg Farm Plants 2024; pers. obs. at Crûg Farm, August 2023). The whole feel of the plant is different to the previous.