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Julian Sutton (2022)
Sutton, J. (2022), 'Magnolia delavayi' from the website Trees and Shrubs Online (treesandshrubsonline.
Evergreen tree to 12(–18) m tall and 80 cm dbh. Bark grey to black, coarse and fissured. Branchlets stout, dotted with lenticels; olive green, pale yellow-brown pubescent when young. Leaf blade ovate to ovate-oblong, 10–20(–32) × 5–10(–20) cm, leathery; initially tomentose beneath with densely interwoven hairs, and white-powdery, later only with residual hairs on veins; upper surface with long, curved hairs at first, later glabrescent, midvein flat to impressed and with residual hairs; secondary veins 11–16 on each side of midvein, reticulate veins dense and prominent on both surfaces when dry, base broadly rounded to sometimes slightly cordate, margin wavy, apex obtuse to rarely emarginate. Petiole 4–7(–10) cm, densely villous; stipular scar nearly reaching apex of petiole. Peduncle erect, 3–4 cm. Flowers fragrant, cupular, 15–20 cm in diam. Tepals 9 or 10; tepals of outer whorl pale green, oblong, 6–8(–10) × 2–3(–4) cm, margin revolute; tepals of inner 2 whorls milky white or red, obovate-spoon-shaped, 8–11 × 2.5– 3.5 cm; tepals of inner whorl narrower. Stamens ~210, 1.8– 2.5 cm; connective exserted and forming a sharp triangular tip; anthers divergent. Gynoecium ovoid, 3–4 cm, finely yellow villous, apex acute; carpels ~100. Fruit ovoid-ellipsoid, 9–15(–20) cm; mature carpels narrowly ellipsoid, finely yellow villous, completely dehiscing along dorsal suture, apical beak reflexed. Flowering April–June, fruiting August–October (China). Diploid 2n = 38. (Xia, Liu & Nooteboom 2008; Chen & Nooteboom 1993).
Distribution China Guizhou, S Sichuan, Yunnan
Habitat Forests on wet slopes, limestone areas; 1500–2800 m.
USDA Hardiness Zone 8-9
RHS Hardiness Rating H4
Conservation status Least concern (LC)
Grown primarily for its magnificent evergreen leaves, matt sea-green above and glaucous beneath, M. delavayi is most often seen as a large, multistemmed wall shrub in our area. Its calm foliage effect is very different to that generated by the brighter, glossy M. grandiflora. In milder gardens, and outside our area in more Mediterranean parts of Europe, it can form impressively broad, bushy trees.
Of the many (predominantly southeast Asian) species of Section Gwillimia this is the only one hardy enough for inclusion here. Its degree of cold hardiness comes as a surprise given the latitude and altitude from which cultivated material originates (Bean 1981). Its discovery by Western science was part of the fertile 19th century collaboration between French missionary-botanist Jean Delavay, who collected it in Yunnan in 1886, and Paris-based taxonomist Adrien Franchet (Franchet 1889). It was a further 13 years before it was introduced to cultivation by Ernest Wilson on his first expedition for the Veitch nursery (Wilson for Veitch 99 of 1899) from southern Yunnan, where it was growing on both sandstone and limestone in Lithocarpus scrub alongside Pinus armandii; it first flowered under glass at Kew in 1908 (Bean 1981; Howard 1980).
Its leaves are some of the largest seen among temperate evergreen trees. Leathery (‘almost resembling thin plastic’ Treseder 1978) and held rather rigidly on the tree, it is not always easy to see their glaucous undersides, which contrast strongly with the matt green upper surface. This is in sharp contrast to the rather smaller leaves of M. grandiflora, often grown in similar situations, which are glossy above and often red-brown beneath. The emerging leaves of M. delavayi have a brown cast.
The large, ivory-white flowers are in ornamental terms something of a disappointment, lasting for only two to three days. They open during the early evening, and are most noticeably fragrant at night, making a summer night pilgrimage worthwhile. Tepals reflex for a short time over two nights. Flowers appear sporadically from July to September. During the mid 1990s, Sun Weibang of Kunming Botanic Garden, Yunnan, introduced a ‘red’ (some would say ‘pink’) flowered form from the Hua-Fu Mountains, Mon-Din County, where it grew in mixed woodland with M. insignis. Raised from seed, Magnolia delavayi flowers after about 10 years, about half the time taken by M. grandiflora. It does not normally fruit in Britain or Ireland but in California large red ‘cones’ are produced sparsely.
Perhaps most at home in a moisture-retentive loam, it tolerates a wide range of soils, including thin soil on chalk, as at Highdown, Sussex, and calcareous sand (Treseder 1978). It is remarkably wind-tolerant for such a large leaved evergreen. Treseder (1978) describes an established specimen which became subject to coastal exposure when surrounding trees were cleared; subsequent growth was more bushy with smaller leaves, and cuttings from it proved much easier to root (layering is a more common means of propagation if seed is not available).
Free standing specimens are not uncommon in southern and western Britain and Ireland. Large examples include trees at Coleton Fishacre (planted 1925, 12 m × 246 cm in 2015) and Saltram House (16 m × 207 cm, 2015), both coastal gardens in S Devon (The Tree Register 2021). Where the wall is high enough, wall shrubs may develop into tree-sized plants as at Lismore Castle, Co. Waterford, Ireland (planted 1953, 14 m × 174 cm in 2010), while a good specimen in Torquay, Devon grew up in the shelter of a sea cliff. One of the earliest surviving specimens, planted at Borde Hill, W Sussex in 1911, has thoroughly outgrown the more modest wall it was planted against before the species’ hardiness was understood (10 m × 216 cm, 2015 – The Tree Register 2021). It seems likely that most older specimens derive from the Wilson collection, although pink-flowered plants are in the nursery trade and appearing in gardens.
Elsewhere in Europe the species suits more coastal parts of France, with magnificent specimens outside our area on the French and Italian Riviera, for example at Villa Taranto. It is recorded from several Belgian collections, mostly as younger trees (Plantcol 2021) and as far east as Bonn, Germany (Bonn University Botanic Garden 2021).
This is a very rare plant in North America, in a few collections on the Pacific Coast (Jacobson 1996). A large, multistemmed tree at Berkeley dating from 1959 is notable. There are younger examples in California from Li 11621 (Yunnan, about 1998) at Sonoma Botanical Garden and the San Francisco Botanical Garden (Quarryhill Botanical Garden 2021), while in Vancouver, BC there is a still younger 2012 accession from JN 11072 in the David C Lam Asian Garden (University of British Columbia 2021). The species seems very difficult to establish in the southeast, Figlar (2005) suggesting that summer heat might be the problem. A pink flowered form now grows at the JC Raulston Arboretum, however (JC Raulston Arboretum 2021).