Cornus officinalis Siebold & Zucc.

Cornus officinalis effectively represents the East Asian form of C. mas, the two species apparently descending from an ancestral population that was severed when the centre of the range dried and cooled during the mid Miocene c. 11 Ma (Du et al. 2023). The trees are similar enough to have deceived even the most knowledgable on occasion (see the entry for ‘Spring Glow’), though there are botanical differences that allow the two to be separated. The leaves of C. officinalis have more vein pairs (6–7, against 3–5 in C. mas), the number of flowers in an inflorescence is greater (Siebold & Zuccarini 1835), and the individual flowers are a richer yellow, borne on longer pedicels (Weaver 1976). Mature specimens of C. officinalis are also typically more upright and vase-shaped in habit, develop strikingly attractive exfoliating bark, and (depending on situation and variety) the autumn foliage may develop long-lasting red-purple colour. These characteristics combine to make C. officinalis the more garden-worthy of the two species in the eyes of many growers. The tufts of brown hairs in the vein axils on the leaf undersides are also diagnostic when present, though this character appears to be inconsistent (Dirr 2009). This type of axillary pubescence (acarodomatia) is a morphological adaptation of the leaf to accommodate commensal mites, a phenomenon whose taxonomic significance is still poorly understood (see the discussion under ‘Domatia’ in the genus entry). It is found in different forms throughout the genus, including in C. mas, though it differs in appearance.

The natural range of Cornus officinalis is China and the Korean peninsula. In China, the species is known as the Mountain Cornel (Shan-zhu-yu), though it appears to be rare as a wild plant – Mikinori Ogisu (pers. comm. 2026) has seen isolated trees in the eastern provinces Anhui and Jiangxi. Its wild status in Korea is not known; Wilson (1919) reported Korean trees 10.5 m tall, 120–150 cm in girth. Cornus officinalis was first described scientifically by von Siebold from cultivated trees in Japan (Siebold & Zuccarini 1835; Akiyama et al. 2016), where it had been introduced around 1720 during the Tokugawa (Edo) period (1603–1868) as an ornamental garden and temple tree, as well as for its medicinal uses (Levy-Yamamori & Taafe 2004). Sargent (1894) described a group of ancient trees at the Botanic Garden in Tokyo (originally a medicinal garden) – ‘bushy plants, perhaps thirty feet tall, with bent and twisted half-decayed trunks, and contorted branches, which form broad thick round heads’. In modern Japan, the tree may be seen trained as a niwaki or sometimes a bonsai.

The fruits of Cornus officinalis are red drupes similar to those of C. mas, though less palatable and often remaining on the tree into the next year’s flowering (Pirc 2015). Siebold reported its medicinal use as an infusion for the treatment of inflammatory conditions in Japan (Siebold & Zuccarini 1835), and noted that the fruit (i.e. the dried pulp) was widely obtainable in pharmacies, whence the scientific name. The fruits are also an important component of the Chinese pharmacopoeia, included in Li Shizhen’s 1578 Ben Cao Gang Mu (Li Shizhen 2012) for the treatment of various genito-urinary complaints. Unlike its European sister species, Cornus officinalis has not historically been cultivated for culinary use. A number of large-fruited varieties are now being trialled by the Höheren Bundeslehr- und Forschungsanstalt, Vienna, though these may be hybrids with C. mas (Pirc 2015). The species is apparently self-fertile (Dirr 2021), the fruit ripening in September in European conditions (Cappiello & Shadow 2005).

Cornus officinalis is reputedly not quite as hardy as its European relative, though Dirr (2009) reported a tree at the Secrest Arboretum, Ohio, that survived –29°C, and recently revised his hardiness assessment from Zones 5–8 to Zones 4b-8 (Dirr 2021). Where the two species are grown in proximity, flowering in C. officinalis is earlier than in C. mas by 10–14 days (Dirr 2021). Gayraud (2013) notes that inflorescences are less affected by frosts than those of the later-flowering C. mas. In southeast England, trees often flower as early as mid to late January, making it a valuable and welcome addition to the winter garden, worthy of wider planting in its best forms (see under Cultivars). In botanical collections, spontaneous hybrids with Cornus mas have been observed (Morozowska, Gawrońska & Woźnicka 2013); Junker’s Nursery, Somerset, UK offers an unnamed hybrid, received from the JC Raulston Arboretum, North Carolina (Junker 2022).

Dirr (2021) finds the tree to have broad tolerances with respect to siting and soil, though at northern latitudes a position in full sun would be prudent – if nothing else, the remarkable late-winter display deserves a spot where it can be seen to its full effect. Like Cornus mas, the tree is long-lived, and some of the earliest North American introductions are thriving today, among them a specimen at the Arnold Arboretum planted in 1922.

Propagation is from cuttings or seed, with high germination rates after three months’ warm then three months’ cold stratification (Dirr 2009, 2021).