Enkianthus perulatus (Miq.) C.K. Schneid.

Certainly one of the gems of the genus, White Enkianthus is a widely grown dainty and decorative shrub; a well-grown, mature specimen is a picture of refinement. Discovered in 1859 in the neighbourhood of Nagasaki, Japan by Sir Rutherford Alcock, it was introduced to western cultivation some ten years later by Messrs. Standish (Bean 1981). Its compact form, habit of blooming prolifically before or just as the leaves emerge, adaptability to cultivation, and its consistently splendid autumn colour conspire to warrant all the accolades it has received.

Although small, the pure white, daintily nodding flowers occur in profusion and are all the more effective as they largely appear on bare stems. The terminal inflorescences are umbellate, helping to distinguish this species from E. subsessilis and E. nudipes in which the inflorescences are racemose (R. White pers. comm. 2023); upon close inspection, the flowers are urn-shaped, the corolla mouth formed by a constriction below the short, reflexed lobes. Plants are relatively slow growing to perhaps 2 m tall and, in time, twice that in width. Like most Enkianthus they tend to be decidedly upright in youth, but will gracefully broaden into a dense, mounding shrub that, in form, is not unlike a low, spreading dissected leaf form of Acer palmatum. Turning shades of brilliant yellow, orange and various shades of red including a vibrant vermilion, the autumn foliage of White Enkianthus easily rivals that of the most intensely colored maple. In shade its colour is much less intense. For garden use in Japan, observed Ernest Henry Wilson (Wilson 1927): “the low, round-topped E. perulatus” is favoured and is “planted in almost every garden in Japan.” It remains a staple in Japanese gardens and responds very well to regular pruning as evidenced by ancient specimens maintained in tightly sculpted forms; not surprisingly, this species is also widely used as a subject for bonsai.

Along with two other Japanese compatriots (E. campanulatus and E. cernuus f. rubens), White Enkianthus is quite common in cultivation in botanic gardens and arboreta throughout Europe and North America, at least where conditions are amenable to their growth. Even though it is clearly a very desirable plant with a long history of cultivation, the vast majority of plants in botanic gardens are of cultivated origin. Wild-source material is currently to be found at the Sonoma Botanical Garden near San Francisco, the Rhododendron Species Botanical Garden near Seattle, and the Arnold Arboretum near Boston, Massachusetts. Perhaps because of their slower growth rate, plants are not widely available from commercial sources; only five sources are listed in the RHS Plant Finder (RHS 2022) and in North America, to actually secure a plant, one has to be quite dedicated to the task of locating a commercial source. The often low branching makes propagating this species by layering an attractive option where only one or two plants are desired.

In 1976, E. taiwanianus was described as a new species from Taiwan. Fewer than 20 years later Mark Flanagan and Tony Kirkham encountered this species during their explorations in 1992. They write, “We are delighted to find the recently named E. taiwanianus, here forming a tall, narrow, flat-topped shrub…its leaves turning a beautful orange-red colour” (Flanagan & Kirkham 2005). Their seed collections might have represented the first introduction of this taxon to western cultivation, however, most accounts of the genus consider this to be conspecific with E. perulatus, including Plants of the World Online, whose treatment is followed here (Plants of the World Online 2022). Nevertheless the Taiwanese populations are interesting, and of conservation concern as E. taiwanianus was listed as rare in the 1997 IUCN Red List (Walter & Gillett 1998).