Diabelia serrata (Sieb. & Zucc.) Landrein

Diabelia serrata is a complex taxon which has probably evolved through recent introgression with sympatric species; in attempting to synthesise its taxonomy Landrein & Farjon (2020) recognise eleven formae, including f. wenzhouensis (endemic to China) and f. sanguinea with interesting, peach-coloured pink, orange and white flowers.

The species was introduced to the UK in 1879 by Charles Maries from Mount Fuji and persists in just a few collections in the west, though it was dismissed by Bean as ‘of little worth’ as a garden plant (Bean 1976). Most of the wild forms have ‘poached egg’ yellow and white blooms which individually recall that of the European herb Common Cow-wheat (Melampyrum pratense), but are rather bigger. At the Royal Botanic Garden Edinburgh, plants accessioned under 19940187 were collected in Shikoku by Yuji Kurashige (Kurashige 665) under the name var. buchwaldii (Graebn.) Nakai (Royal Botanic Garden Edinburgh 2021) (f. buchwaldii (Graebn.) Landrein). Michael Dirr (Dirr 2009) describes a ‘beat up’ plant which once grew at the Royal Botanic Gardens, Kew, and a much better one in the more continental climate of the Keith Arboretum in North Carolina. However, the vernacular name which is sometimes encountered in American literature, ‘Glossy Abelia’, is puzzling since this fully-deciduous plant has thinner and matter leaves than any of the widely-cultivated Chinese forms of Abelia, suggesting the possibility that an imposters have been cultivated in America under this name. In the wild, D. serrata is often found over limestone (Landrein & Farjon 2020), though The Hillier Manual of Trees and Shrubs suggests it is ‘not for shallow chalk’ (Edwards & Marshall 2019).