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The Wynkcoombe Arboretum
Dan Crowley (2020)
Crowley, D. (2020), 'Acer obtusifolium' from the website Trees and Shrubs Online (treesandshrubsonline.
A late-deciduous shrub or tree to 7 m, often much smaller. Bark grey to brown, roughly fissuring with age. Branchlets glabrous, brown. Buds ovoid, small, with 8–10 pairs of imbricate scales, brown, ciliate with grey hairs. Leaves coriaceous, base truncate to rounded, entire to 3-lobed, 3–6 × 4–10 cm, lobes oblong, apex obtuse, margins entire to undulate, upper surface dark to grey green, lower surface paler, glabrous; petiole to 5 cm long, green; autumn colours none. Inflorescence terminal, corymbose, pendulous, 9–16 flowered. Flowers greenish-yellow, 5-merous, sepals oblong, 0.4–0.5 cm long, petals obovate to oblong, as long as sepals, stamens 8, inserted inside the nectar disc. Samaras to 2 cm long, red, wings spreading at an acute angle; nutlets rounded. Flowering in March, with the new leaves, fruiting later. (van Gelderen et al. 1994; le Hardÿ de Beaulieu 2003; Gregory 2005).
Distribution Cyprus Israel Lebanon Syria
Habitat Mountain sides and along watercourses up to 1000 m asl.
USDA Hardiness Zone 7-8
RHS Hardiness Rating H5
Conservation status Least concern (LC)
Largely restricted to specialist collections, Acer obtusifolium appears present in collections only from relatively recent plantings. The species wasn’t discussed by Bean (1976a) though it was included by Rehder (1927–1940) under its synonym, A. syriacum, with an introduction to cultivation given as 1903. It is closest to its eastern Mediterranean compatriot A. sempervirens, the two most easily distinguishable by their respective leaf size, with those of A. obtusifolium being the larger of the two. That said, similar growing conditions tend to see the two appear very close to one another in this respect, though the leaves of A. obtusifolium are often somwhat downcurved at the edges, whereas those of A. sempervirens are held flat. Furthermore, those of A. obtusifolium are seemingly never as small as they can be in A. sempervirens, which in some forms are as small as 2 cm long.
As usual, it is prudent to observe several leaves when making determinations, and provenance also helps! Two plants grown from a collection made by Ron McBeath, in a dry forest dominated by Pinus brutia in Cyprus in 1993 (McB 2692), grow at Westonbirt and have made rounded, somewhat scruffy, but quite hardy plants. The UK and Ireland Champion grows at the Sir Harold Hillier Gardens, Hampshire, and measured 12.4 m tall in 2017 (The Tree Register 2018). le Hardÿ de Beaulieu (2003) advises that the species is only really suited to a mild climate akin to that of southern England. Despite this a tree of 4 m was recorded at Sheffield Botanical Gardens, South Yorkshire in 2015 (The Tree Register 2018), though many other tender plants grow in this city-centre location (J. Grimshaw, pers. comm. 2020). Indeed, Gregory (2005) describes A. obtusifolium as the hardiest ‘evergreen’ maple, which is also, unsurprisingly, very resistant to drought and tolerant of poor soils. The species also grows at Arboretum Wespelaar, Belgium (Arboretum Wespelaar 2018) though it is restricted to a greenhouse at Rogow Arboretum, Poland (P. Banaszczak, pers. comm. 2020). It is used as a hedging plant in Cyprus (le Hardÿ de Beaulieu 2003).