Berberis oiwakensis

Taxonomy

Berberis oiwakensis was first scientifically described and named Mahonia oiwakensis by Bunzō Hayata in 1916. One year later Hisayoshi Takeda described a species that he named Mahonia lomariifolia. Under that name, it was considered to occur only in mainland China, while Mahonia oiwakensis was limited to Taiwan. Modern taxonomic sources unite the two as a single species with priority going to the first description. Because of differences between the Taiwanese and mainland Chinese plants, Julian Shaw described them as separate subspecies of Mahonia oiwakensis in 2011. However, this has not yet been accepted by the majority of botanists. In addition, there has been a longstanding disagreement on if Mahonia should be more properly classified as a synonym of Berberis. A paper was published by Joseph Edward Laferrière in 1997 summarized the arguments in favor of classification in Berberis and published a new name for the species, Berberis oiwakensis. As of 2023, this is the most widely accepted classification.

Hybrids

Berberis oiwakensis is one parent of the important garden hybrid Berberis × hortensis, which includes popular cultivars such as 'Charity', 'Winter Sun' and 'Lionel Fortescue' (the other parent is Berberis japonica). It is also a parent of the cultivar 'Arthur Menzies', though with Berberis bealei as the other parent. In the wild in Taiwan, Berberis oiwakensis appears to hybridize with wild Berberis japonica.

Berberis oiwakensis subsp. lomariifolia has gained the Royal Horticultural Society's Award of Garden Merit.