Trees to 12 m tall. Branchlets hairy or glabrous. Leaves papery 8–12 × 4–6 cm, oblong to ovate-oblong, lower surface sparsely grey-brown stellate pubescent on veins, seven to ten secondary veins on each side of the mid-rib, margin serrate to subentire, apex slightly curved and acute to rarely acuminate; petiole 0.7–1.5 cm. Inflorescences racemes terminal, 8–10-flowered, 9–15 cm long; pedicel 0.2–0.4 cm. Flowers 1.8–2.7 cm long; calyx five-toothed, corolla tube c. 0.1 cm; lobes c. 1.5 cm long, elliptic to elliptic-obovate. Stamens shorter than corolla; filaments sparsely white stellate villose on free part. Fruit globose to ovoid, 0.8–1.3 cm long, rugose, densely yellow-brown to grey-yellow stellate tomentose, apex apiculate (Hwang & Grimes 1996).
Distribution China Guizhou, Henan, Hubei, Hunan, Shaanxi, Sichuan.
Habitat Mountain slopes and forest edges; altitude 300–900 m.
USDA Hardiness Zone 5a-9b
RHS Hardiness Rating H5
Another Chinese Styrax first discovered by Augustine Henry in the 1880s and then introduced to cultivation by E.H. Wilson in 1900, under Wilson 915, via Veitch and Sons. Wilson’s collection flowered for the first time in 1909 in the UK at Coombe Wood Nursery, owned by the Veitch family, and was illustrated for Curtis’s Botanical Magazine in 1910.
Despite being described as hardy down to –15°C it does require shelter from drying winds, and good, moist soil. Unlike Styrax dasyanthus, also introduced by Wilson in 1900, this species has persisted in cultivation and there are examples in gardens across the British Isles. The more recent introduction of S. hemsleyanus by the late Edward Needham, under the name S. huanus, is now being cultivated in a number of gardens in the UK (Grimshaw & Bayton 2009). We follow the treatment of Huang, Fritsch & Shi (2003) with S. huanus being treated as a synonym of S. hemsleyanus, in contrast to the Flora of China account, see Hwang & Grimes (1996).
S. hemsleyanus is relatively rare in cultivation when compared with some of its cousins, but it occurs in collections in New Zealand, for example at Paloma Garden, Whanganui (T. Christian pers. comm. 2018), and in North America, for example at the JC Raulston Arboretum where there is a good collection of Styrax generally – this specimen was 8 m when measured in 2009 (JC Raulston Arboretum 2018). As with many Styracaceae in the UK and Ireland the best examples are to be found in the southern collections. Sidbury Manor in Devon has a 13 m tall example, and the National Trust property Bodnant in north Wales has an almost equally large specimen at 12 m (measured at 36 ft [c. 10 m] in Bean 1981b). Caerhays in Cornwall had a 40 ft [c. 12 m] specimen measured in 1971 (Bean 1981b), but this is no longer extant, however the estate does several other examples of varying ages. Nymans in West Sussex has a 10 m tall specimen that might be two plants that have fused at some point in the past while the most northerly example recorded in the British Isles is a 6 m example at Cluny House Gardens in Perthshire.
Styrax hemsleyanus is occassionaly mistaken for S. obassia when not in flower, but the leaves of S. obassia are rounder, more coarsely toothed, and much more downy beneath. In the UK at least S. hemsleyanus is generally earlier to flower than the much more commonly grown S. japonicus.