Small tree to 10 m with narrow, upright habit. Branchlets dark purple and densely hairy when young, robust. Buds dark purple, ovoid; scales glabrous or sparsely hairy at margin. Leaf blade ovate, 6–12 × 4–7 cm, usually tomentose beneath; base rounded to cordate, apex acute; margin doubly toothed, often with 3–5 lobes on each side; petiole 2–3.5 cm. Inflorescence an 8–12-flowered corymb, 5–9 cm across; pedicels 1.5–3 cm, hairy. Flowers about 1.5 cm diameter, in late spring, May in the wild. Sepals triangular-ovate, 3–4 mm, persistent, both sides tomentose; petals white, suborbicular, about 8 mm; stamens 20–25, unequal, slightly shorter than petals, anthers yellow; styles 5, nearly as long as stamens. Fruit typically red, often with white dots, August to September in the wild, globose, 1–1.5 cm diameter, with a cup shaped depression at the apex; flesh astringent, gritty with stone cells. (Gu et al. 2003; Cullen et al. 2011; Bean 1981).
Distribution Myanmar China Guizhou, Hubei, Shaanxi, Sichuan, Xizang, Yunnan.
Habitat Mixed forest on slopes or by streams; 1600–3800 m asl.
USDA Hardiness Zone 5-9
RHS Hardiness Rating H6
Conservation status Data deficient (DD)
One of the more familiar small-fruited apples of China, the Yunnan Crab divides horticultural opinion. While few would consider it among the best in flower, usefully late as it is, it is more likely to impress in fruit. Typical forms have rich, dark red fruit, ‘so astringent, it immediately dries the mouth out’ (Drinkwater 2013). In some collections (e.g. CLD 1463 – Royal Botanic Garden Edinburgh 2020) they are brown when ripe. Bean (1981) enthused over how, when first exhibited, the branches of var. veitchii ‘bore a wonderful crop of red crabs and were exceedingly ornamental’; but to Jacobson (1996), a non-believer, ‘even if the fruit is abundant it is ornamentally nil.’ It is capable of good orange-red autumn colour.
Several other species with a persistent calyx share a similar general appearance. M. prattii and the rare M. ombrophila, both with unlobed leaves, are probably the best candidates for its closest relatives (e.g. Nikiforova et al. 2013; Rushforth 2018); M. honanensis has only 3–4 styles.
A widespread tree in western and central China, its ability to grow under poor conditions gives it value as a rootstock for other apples in its native range (Gu et al. 2003). It became known to western science through a collection made by Père Delavay in 1886 in the Heishanmen, north west Yunnan: Delavay crossed this botanically rich mountain range, with a pass at 3000 m, more than 60 times in the course of his missionary work (Kilpatrick 2014). Franchet named it (as Pyrus yunnanensis) from Delavay’s specimens. It was introduced to European cultivation by the Veitch nursery, from a collection made in Western Hubei by Ernest Wilson in 1901 (Wilson for Veitch 670 – Sargent 1916). This was soon followed by further collections by both Wilson and George Forrest. Widely distributed in an area whose species-richness and reputation for providing hardy, garden-worthy plants has attracted many collecting expeditions, it is no surprise that there has been a steady flow of more recent introductions. The variation within this group of species is not fully understood, and inevitably some collections are labelled ‘aff. yunnanesis’ and so on.
One such collection is CLD 1447 (Yunnan, 1990), grown at RBG Edinburgh and Ness Botanic Gardens. Introduced as M. yunnanensis, it is an apomictic triploid with a usually deciduous calyx, presumably an undescribed microspecies of hybrid origin (H. McAllister pers. comm. 2020).
The name var. veitchii has been current in horticulture since it was first used by Rehder (1923); the original Wilson collection was placed here, and plants labelled var. veitchii are more common in cultivation. It was originally characterized by larger, distinctly lobed leaves than the type variety, usually cordate and tending not to retain the hairs beneath; and by smoother, more colourful fruits; it was said to have a more easterly distribution (Rehder 1923). Flora of China (Gu et al. 2003) accepts the variety, although restricts the distinction to more guarded comments on leaf shape and hairiness. The distinction seems not to be very clear; intermediate forms are known (Bean 1981), and many more recent collections are not assigned to either variety in catalogues (e.g. Royal Botanic Garden Edinburgh 2020). Some features of var. veitchii as seen in gardens are perhaps merely the characters of a particular collection (see below).
Malus yunnanensis is well represented in British collections. Large, old specimens include trees at Crathes Castle, Aberdeenshire (12 m × 255 m, 2018), Wakehurst Place, Sussex (13 m × 158 cm, 2015) and Cambridge Botanic Garden (planted 1923, 9 m × 84 cm in 2014, with ‘huge leaves’ – The Tree Register 2020). There is a tree dating from 1922, from an un-numbered Forrest collection at the Royal Botanic Garden, Edinburgh (10 m × 159 cm, 2015 – The Tree Register 2020). Both RBG Edinburgh (Royal Botanic Garden Edinburgh 2020) and the Yorkshire Arboretum (J. Grimshaw pers. comm. 2020) have multiple accessions from more recent wild collections, allowing comparisons to be made. Quite widely hardy in continental Europe, there is a wild provenance tree dating from 1995 at Gothenburg Botanic Garden, Sweden, and a specimen of nursery origin at Meise Botanic Garden, Belgium (Gothenburg Botanical Garden 2020; Meise Botanic Garden 2020).
Yunnan Crab has been grown in North America since 1907, when a specimen from the original Wilson introduction was brought to the Arnold Arboretum from the Veitch nursery; seed of the type variety from another Wilson collection followed a year later (Rehder 1923). These early introductions are now gone from the Arnold, but there are trees dating from two collections made in the same part of western Hubei in 1980, SABE 1301 (labelled var. veitchii; 25 cm dbh in 2017) and SABE 1556 (27 cm dbh in 2017 – Arnold Arboretum 2020). There is a significant number of specimens from four more recent wild collections at the David C. Lam Asian Garden, Vancouver (University of British Columbia 2020) and one from SABE 1771 (western Hubei, 1980) at Berkeley, CA (University of California Botanical Garden 2020). For all its charms, this species is not often seen outside specialist collections in our area.
A particularly fine clone, a seedling selection made by Lawrence Banks at Hergest Croft, Herefordshire, UK.
Growth Rate/Size: Small (<4 m)
Form/shape/habit: Broadly spreading
Foliage: Large, lobed; good autumn colour
Flower colour: Ivory white
Flower size: Medium (<4 cm)
Flower form: Single
Flower season: Late
Fruit size: Small (<2 cm)
Fruit shape: Round
Fruit colour: Bronze, red blush
Fruit season: Mid
Disease resistance/susceptibility: Resistant
Date of introduction: 2017
(Description duplicated under Malus Cultivars G-I ‘Golden Glory’)
See notes above on the issues around this variety. As usually seen in cultivation – perhaps the descendants of Wilson’s original collection – this makes a taller tree with erect branches; the leaves are distinctly lobed with a cordate base; fruit colour is usually a good red (Edwards & Marshall 2019; Jacobson 1996; van den Berk Nurseries 2020). This is the most widely grown form, at least in Europe, sometimes offered by large tree nurseries for amenity plantings thanks to its tolerance of a wide range of soils.