Tree to 30 m, 50 cm dbh. Bark grey-white, smooth. Branchlets pale green and glabrous with distinctive bamboo-like internodes. Leaves evergreen, thin and leathery, 6.5–15 × 2–5 cm, ovate to oblong or elliptic, leaves glabrous on both surfaces, pinkish red when immature, 7–15 secondary veins on each side of the midrib, margins entire; base broadly cuneate to rounded; apex at least shortly acuminate; petiole 1.5–2.5 cm long; stipules free from the petiole. Androdioecious: flowers terminal, fragrant; male flowers white with 9–12 tepals; outer three tepals thin, obovate and ~4 × ~2 cm, sometimes tinted red; inner tepals fleshy and obovate to spathulate, stamens ~30 with red filaments; hermaphrodite flowers similar to male but gynoecium sessile with 10–20 green carpels. Fruits reddish pink, ~6 cm long, ellipsoid to ovoid; ripe carpels rhomboid and united before maturity, dehiscing along the dorsal suture. Flowering April to May, fruiting September to October (China). Hexaploid 2n=114. (Xia, Liu & Nooteboom 2008; Liu et al. 2004).
Distribution China SE Xizang, Yunnan Vietnam N
Habitat Evergreen broadleaved forest, 1200–1500 m.
USDA Hardiness Zone 9
RHS Hardiness Rating H3
Conservation status Data deficient (DD)
Taxonomic note Chen & Nooteboom (1993) treated this species as a synonym of Magnolia nitida, but like M. lotungensis it is a distinct hexaploid (Chen et al. 2000). See Magnolia laevifolia for commentary on specific name yunnanensis.
Still a species with ‘experimental’ status in cultivation, Magnolia yunnanensis is a significant forest tree. In southern Yunnan it forms the upper canopy in an important class of tropical montane rain forest, along with species such as Nyssa sinensis, Cinnamomum javanicum and Calophyllum polyanthum (Zhu, Wang & Li 2006). A member of Section Gynopodium, it can be distinguished from the better known M. nitida by its having both male and hermaphrodite flowers on the same plant (versus all hermaphrodite).
Originally described as Parakmeria yunnanensis, it is sometimes confused in name with Magnolia laevifolia, which was first described and became widely known as Michelia yunnanensis. A trawl of internet images and nursery descriptions in 2021 suggests that while several British nurseries were listing Magnolia yunnanensis, at least some of these were actually selling the tried-and-tested M. laevifolia (J. Sutton pers. obs.).
Enthusiasts such as Tom Hudson and Sean Hogan (pers. comms. 2007) are impressed by Magnolia yunnanensis, admiring it for its elegant narrow foliage and pinkish red new growth (‘bronzy orange to lipstick crimson’ according to Peter Wharton), as well as a more gracile habit than its relatives M. lotungensis and M. nitida. It is growing well for both but has yet to flower at Tregrehan, where the largest tree is at least 15 m tall (T. Hudson pers. comm. 2022); in Oregon a tree of 5 m had produced one flower by 2008. It is also flourishing in Vancouver, and its prospects as a reasonably hardy tree for the milder parts of our area seem good (Wharton 2007), although it is probably less hardy than M. lotungensis, –12 °C being suggested as the minimum it will normally tolerate (Hogan 2008). An early introduction was made by Monrovia Nurseries but it has been collected on several other occasions since, by expeditions and private collectors.
In a southern Chinese context, Li et al. (2020) rated it highly in urban planting trials carried out in Ganzhou, Jiangxi, based on its tolerance of drought and a wide temperature range, as well as its form and appearance.