Acer acuminatum Wall. ex D. Don

Endemic to the Himalayas, Acer acuminatum is one of four species belonging to the exclusively Asian Section Arguta. Often noted as occurring largely in the western part of the Himalayan range (e.g. Lancaster 1981), it was recorded in southern Tibet in 2007 (Chen 2007), representing an eastern extension of its known range.

Acer acuminatum was introduced to North America in 1848 (Rehder 1927–1940), though its date of arrival to Britain is unclear. An older tree at RBG Kew (1969.13322), presumably an early introduction, is noted by the Tree Register for its impressive dimensions, with a diameter measured at 39 cm in 2016 prior to its decease (The Tree Register 2025: note that 1969 numbers at Kew usually refer to specimens present in the collection that year, when the current system of accessions was instituted). Other notable historic trees included a charismatic, self-propping female in the Old Arboretum at Westonbirt, measured at 13.5 tall in 2009 (Johnson 2011), but felled due to failing health in 2017. Planted in 1943 (Johnson 2011) though of unknown origin, it appears to have produced viable seed. A putative seedling has successfully established itself close to where its parent grew.

More recent, documented introductions of the species include Tony Schilling’s introduction to the UK from eastern Nepal in the 1980s (Clarke 1988). Plants grown from this gathering were represented at Wakehurst though no existing plants remain there (O. Steed-Mundin, pers. comm. 2024). Current examples at Wakehurst include material collected by Charles Howick and Bill McNamara in the Great Himalayan National Park, Himachal Pradesh, India in 1993. A plant of H&M 1822, collected from a tree growing at 2720 m asl was measured at 8 m tall in 2022; one from H&M 1921, collected at 3085 m, was recorded at 13 m in the same year (The Tree Register 2025). A plant from the latter collection was measured at 9 m tall in 2019 at Howick Hall. The UK’s current tallest example grows in Park Wood at Hergest Croft, Herefordshire, measured at 14 m tall in 2023, from a 1998 planting (The Tree Register 2025).

Numerous plants raised from seeds collected by Howick and McNamara are also represented in North American collections. An individual of H&M 1858 grows in the David C. Lam Asian Garden at the University of British Columbia Botanical Garden – it was quick growing in youth (D. Justice, pers. comm. 2026). The aforementioned H&M 1822 has also been recorded at the Morris Arboretum, Pennsylvania and at Sonoma Botanical Garden, California (American Public Gardens Association 2017). The species is also well represented at Arboretum Wespelaar, Belgium. Plants there include a tree acquired from Plantentuin Esveld, the Netherlands, which turns a good yellowish orange in autumn, as well as wild origin material from Tibet. One such plant is proving very vigorous in youth, having attained more than 5 m in five years (pers. obs.).

Acer acuminatum is unlikely to be confused with species within its own section, though may be mistaken for A. caudatum (a mistake made by Wallich – see account of that species for more information), belonging to Sect. Spicata, and A. pectinatum in Sect. Macrantha. Similar in leaf shape and lobing, both are pubescent beneath the vein axils, and A. caudatum (and other members of Sect. Spicata) have rougher-textured leaves, while the leaf margins of A. pectinatum are more finely toothed. Belonging to different sections, both also possess markedly different inflorescences. The species was previously grown at RBG Kew from seed received as A. pentapomicum (Bean 1976), another Himalayan species though quite distinct from A. acuminatum, and encountered far less in collections.