Cladrastis wilsonii Takeda

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Credits

Owen Johnson (2023)

Recommended citation
Johnson, O. (2023), 'Cladrastis wilsonii' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/cladrastis/cladrastis-wilsonii/). Accessed 2024-03-28.

Synonyms

  • Cladrastis lichuanensis Q.W. Yao & G.G. Tang

Tree to 16 m, often with a spreading habit from a short bole. Bark grey or grey-brown, thin and smooth, with a pattern of round lenticels. Shoots slender, pubescent at first. Buds concealed through summer within the swollen base of the leaf-stalk, which is also pubescent. Leaves with 8–11 leaflets, each 3.5–14 × 1.8–6.5 cm, with a broadly cuneate base and an acute tip, widest at or above halfway up; they are carried alternately on the rachis on petiolules 4–5 mm long, which are pubescent in early summer; leaflets are pale green or slightly greyish beneath with dense golden hairs under the veins. Inflorescence terminal or axillary, 10–28 cm long, drooping; pedicels with greenish hairs; flowers opening May-July (in China). Calyx campanulate, 7–8 mm, with triangular teeth, yellow-brown tomentose. Corolla white; flower c. 20 mm. Ovary densely sericeous. Fruit-pods oblong, flattened, 4.5–8 × 0.8–1 cm, beaked at the tip. Seeds 1–5, grey-brown, reniform, ripening August-September (in China). (Flora of China 2021).

Distribution  China Anhui, Fujian, Gansu, Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangxi, Shaanxi, Shanxi, Sichuan, Yunnan, Zhejiang.

Habitat Hill forests at 1000–1500 m asl.

USDA Hardiness Zone 6

RHS Hardiness Rating H6

Conservation status Least concern (LC)

Through the twentieth century, several trees were introduced under the name Cladrastis wilsonii, both to Europe and North America, but careful study, inspired by the original coverage in Trees and Shrubs Online in 2021, has suggested that here is an example of one of those plants for which every example grown in the West is quite likely to have been an imposter.

Cladrastis wilsonii differs from C. delavayi in its slightly few leaflets which are boat-shaped rather than oblong, have pointed tips, and are less silvery underneath; its flowers are individually larger but are carried in smaller and more drooping heads. Material was first introduced as C. wilsonii by E. H. Wilson in 1907 (W 1102). By this stage in his plant-hunting career, Wilson’s seed consignments were received by the Arnold Arboretum in Massachusetts; a single seedling was obtained by the Royal Botanic Gardens, Kew, in 1910 (Bean 1976). This was propagated by grafting on the American C. kentukea but – possibly because of compatibility issues – all the scions at Kew are said to have died by the 1980s without ever flowering (Clarke 1988), though they did at least show a good yellow autumn colour (Bean 1976). However, W 1102 seems to have been a field number covering various collections of both C. wilsonii and C. delavayi, and the trees at Kew seen by Desmond Clarke resembled C. delavayi in foliage features (Clarke 1988). Another specimen at the RHS Garden at Wisley, also believed to be from W 1102 and labelled C. wilsonii, was nearing the end of its life in 2000 and was cut hard back in 2006 (Tree Register 2021). Before its final demise, Matt Pottage succeeded in raising grafts (N. Macer pers. comm.); scions from these have sometimes been available from PanGlobal Plants (Pan-Global Plants 2020). The scion replanted at Wisley in 2009 tends to C. delavayi in foliage features (as of 2023, it had not yet flowered), though the leaves are less markedly oblong than is usually the case within the cultivated UK population (Jan De Langhe pers. obs.; this tree is illustrated within the introduction to Cladrastis on this site). In the United States, any survivors from Wilson’s introduction to the Arnold Arboretum had been lost by 1977 (Robertson 1977), possibly for lack of hardiness in Massachusetts.

Another purported introduction of Cladrastis wilsonii to England was in 1996, when seed was distributed by Shanghai Botanic Garden (SBG 96/213). However, the example raised by Tom Hudson at Tregrehan has sub-opposite leaflets and lateral buds exposed through summer, and appears to be Maackia hupehensis (Jan De Langhe pers. obs.) Another seedling from SBG 96/213, planted by James Harris in the New Arboretum at Mallet Court in Somerset was a thriving young 3 m tree in 2017, when the author did not check its authenticity.

In France, Cladrastis wilsonii is listed by Pépinière Aoba (Pépinière Aoba 2021), but material was not yet ready for sale in 2023. The illustration on this site, provided by Shanghai Botanic Gardens, does at least appear to show genuine C. wilsonii.

Most of the trees from the forests where Cladrastis wilsonii grows wild make good garden plants in north-west Europe and flower regularly. With its elegant foliage and potentially spectacular blossom, this is surely a tree which adventurous gardeners should continue to seek out.