Zabelia biflora (Turcz.) Makino

As the (partial) list of synonyms suggests, this is a taxon of questionable extent and diversity; plants of this group are very occasionally cultivated in the west, where they tend to be subject to a similar degree of nomenclatural confusion. 1923 is sometimes cited as the taxon’s date of introduction to cultivation (Dirr 2009); more recently in the UK, Zabelia biflora was commercially available from Larch Cottage Nurseries until 2018 (Royal Horticultural Society 2020). Michael Dirr observed a plant flowering in the Arnold Arboretum in Massachusetts in 1991 (Dirr 2009), while a 2003 accession at Longwood Gardens in Pennsylvania was obtained from the Princeton Nurseries in New Jersey (presumably before the nurseries’ closure in 1995) (Royal Botanic Garden Edinburgh 2021). However, an online (photograph) of a plant purporting to be Z. biflora, apparently taken in the Michigan area, clearly shows Z. tyaihyoni, as do (photographs) of a plant presumably grown as Z. biflora in the University of Wroclaw Botanical Garden in Poland. This species may well be even hardier than its traditionally assessed limit of USDA zone 5–6 may imply.