Acer mandshuricum Maxim.

A highly desirable ornamental tree, Acer mandshuricum develops a somewhat more open crown than other members of Section Trifoliata (Dirr & Warren 2019) and can produce spectacular autumn colour. Plants at Arboretum Wespelaar in Belgium are considered ‘real harbingers of autumn’ usually colouring in the second half of September, though with leaves quick to fall (K. Camelbeke, pers. comm. 2024). The species is also highly rated by Dirr & Warren (2019), who note its apparent disease resistance and rapid growth at seedling stage. It is hampered though by its propensity to suffer damage from late frosts (Bean 1976; K. Camelbeke, pers. comm. 2024). Though there are currently no cultivars of the species in circulation, Dirr & Warren (2019) ‘are hopeful’ (p. 72) that this might soon be rectified.

Acer mandshuricum appears to have first arrived in western cultivation via material received at Kew from St Petersburg in 1904 (Bean 1976), and to the Arnold Arboretum via the same sender two years later (Nicholson 1997). Noted by Bean (1976 p. 209) as ‘a small, deciduous tree, sometimes a shrub’, it can however attain 30 m or more in the wild (Pojarkova 1974; Xu et al. 2008). In parts of its range at least it occurs as part of a remarkable assemblage of maple species: A. barbinerve, A. pictum, A. pseudosieboldianum, A. tegmentosum and A. ukurunduense are all found in its company in the Russian Far East, as observed by Koen Camelbeke and others in 2017. There it grows at the woodland edge to 20 m tall, with some plants also bushy in form (K. Camelbeke, pers. comm. 2024). The tallest recorded example in the UK is at Hergest Croft, Herefordshire, measured at 11 m tall in 2023 (The Tree Register 2023). Examples of 8 m tall grow at Bodant, Conwy, at the Savill Garden, Windsor and at Whitehouse Farm, Kent (The Tree Register 2023).

As with Acer triflorum, much recently introduced material of interest has come via gatherings made by North American collectors. Plants of A. mandshuricum grown from the 1993 NACPEC Heilongjiang expedition are at The Morton Arboretum, Illinois (HLJ 002, HLJ 044) and the Morris Arboretum, Philadelphia (HLJ 002), while material from the 1997 NACPEC Changbai Shan expedition (NACPEC 97135) are at the Arnold Arboretum, Boston (American Public Gardens Association 2017). Prior to these introductions, Bean (1976) noted that the species thrives in New England and sets fertile seed there.

Acer mandshuricum is quickly distinguished from other trifoliolate maples by its smooth bark and leaves with glabrous petioles and narrow, forward facing leaflets. The recently introduced A. sutchuenense is similarly glabrous though with slightly broader leaflets, and has many-flowered infloresences, whereas A. mandshuricum has inflorescences with three to five flowers only (Xu et al. 2008).