Picea alcoquiana (H.J. Veitch ex Lindl.) Carrière

Picea alcoquiana is one of Japan’s four endemic spruces (the others are P. koyamae, P. maximowiczii and P. polita). Along with P. koyamae and P. maximowiczii this species is confined to the Japanese Alps on the Pacific side of central Honshu, but P. alcoquiana has a larger range than either of those narrow endemics. The forests in this part of Japan are famously diverse and contain some of the densest concentrations of temperate conifer species on earth, rivalled only by parts of the Russian Wilderness in the Klamath Mountains of northern California (Debreczy & Rácz 2011). Particularly at lower elevations the broadleaf diversity is even more bewildering; in a single river valley in Yamagashi Prefecture in 2013 the present author noted associates including Acer carpinifolium, A. palmatum, A. pictum, Betula ermanii, Carpinus sp., Castanea crenata, Clethra barbinervis, Fagus crenata, Quercus crispula, Stewartia sp., Viburnum furcatum and Vitis coignetiae (pers. obs. 2013; E00822174).

J.G. Veitch introduced Alcock Spruce from Mt Fuji in 1860 when he accompanied an excursion to the summit led by the British Minister to Tokyo Rutherford Alcock. Unfortunately, Veitch inadvertently collected seed and herbarium material from individuals of this species and from Hondo Spruce (Picea jezoensis subsp. hondoensis) and so Lindley’s description, published the following year, was based on two taxa and thus his name, Abies alcoquiana H.J.Veitch ex Lindl., was invalid (at this time the delimitation of the firs, Abies, and spruces, Picea, was far from settled and many spruces were originally described in Abies). In 1866 Maximowicz published an alternative name, Abies bicolor Maxim., referencing the distinctly bicoloured needles, and in 1906 this was transferred to Picea as P. bicolor (Maxim.) Mayr, a name that would stand for much of the remainder of the 20th century, until somebody pointed out that in 1867 Carrière had re-deployed Lindley’s original epithet in Picea, rather than Abies, and therefore the correct name is P. alcoquiana (H.J.Veitch ex Lindl.) Carrière.

Veitch’s mixed collection of seed germinated well, but the Hondo Spruce seed was either more plentiful or more fertile, for Elwes and Henry would later observe that ‘in gardens most trees named P. Alcockiana [sic.] are in reality P. [jezoensis subsp.] hondoensis’ (Elwes & Henry 1906–1913). Perhaps the initial mixup and the ensuing nomenclatural turmoil dampened enthusiasm for this spruce for it never became popular and has always been rare in cultivation, despite being hardy, tough, and tolerant of most conditions save alkaline soils. W.J. Bean dismissed it as being ‘of no ornamental merit’ (Bean 1976) and as others have observed it is slow growing on both sides of the Atlantic. The better specimens in Britain known to Alan Mitchell averaged less than 30 cm height increase and less than 3 cm girth increase per year through the middle decades of the 20th century (Mitchell 1972) while a recent introduction to the Royal Botanic Garden Edinburgh (EIKJE 227), gathered in Nagano Prefecture in 2013, germinated poorly and seedlings were very slow to grow on (pers. obs. 2013–2018).

Despite its demerits Picea alcoquiana retains a toe-hold in major collections throughout our area and is occasionally met with in historic gardens. If it is becoming more widely sought by collectors it is for its rarity rather than its subtle charm. Among the best in Britain today are two good trees near Dunkeld Cathedral in Perthshire, 25 m tall × 68 cm dbh and 26.5 m × 48 cm in 2017; a tree at Wakehurst Place, Sussex, was 25 m × 67 cm dbh in 2015, while the largest recorded girth is a tree at Scone Palace, Perthshire, 21 m × 85 cm in 2017 (Tree Register 2024). Picea alcoquiana has always performed steadily in the continental conditions of the northeastern United States; the best known to Henry Elwes grew at the Hunnewell Pinetum in Massachusetts (Elwes & Henry 1906–1913). The Arnold Arboretum has several grafted trees received from Hunnewell in 1903; the larger two 68 and 69 cm dbh respectively (Arnold Arboretum 2024). A tree at Arboretum Saint Michel, Saint-Hubert, Belgium, was 82 cm dbh in 2021, but the height was not noted (Arboretum Wespelaar 2024).