Kindly sponsored by a member of the International Dendrology Society.
John Grimshaw (2016)
Grimshaw, J. (2016), 'Stewartia rostrata' from the website Trees and Shrubs Online (treesandshrubsonline.
Deciduous shrub or tree, to 10 m, often multi-stemmed from the base. Bark greyish-brown, finely furrowed; branches ascending; bark on first year twigs not exfoliating; winter buds compressed, c. 5 mm, with 2 or 3 finely pubescent imbricate scales. Leaves (2–)6–10.5 × (1.2–)2.5–4.5 cm, ovate to elliptic, papery, glabrous above with prominent midrib, sparsely appressed villous below, especially on veins, with tufts of hairs in vein axils, margin serrate, apex acute, base rounded; petiole (2–)4–6(–9) mm, shallowly grooved above. Flowers solitary; pedicel 5–7 mm; bracteoles persistent, subopposite, subtending calyx, ovate, (1.2–)1.5–2 × (0.6–)0.8–1.2 cm, leaf-like, margin irregularly undulating, apex acuminate; sepals 5, persistent, similar to bracteoles, ovate, obovate, or orbicular, 1.2–1.8 × 0.7–1 cm, basally connate, margin irregularly undulating, apex acute to rounded; corolla white, lobes obovate to suborbicular, 2.8–3.8 × 2–3 cm, outside finely silky-hairy, margin erose; filaments to 2.5 cm, joined at the base into a 6–8 mm tube and fused to the corolla, pubescent; ovary rounded, densely silky-hairy at base, glabrous above; style 1.6–1.8 cm, glabrous, terminating in a 5-lobed stigma. Capsule subglobose, 1.2–1.6 × 1.4–1.6 cm, apex rostrate. Seeds narrowly winged. Flowering May–July (China). (Ming & Bartholomew 2007).
Distribution China Anhui, Henan, Hubei, eastern Hunan, Jiangxi, Zhejiang
Habitat Forests, especially along streams, 600–1500 m asl
USDA Hardiness Zone 6-7
RHS Hardiness Rating H5
Conservation status Not evaluated (NE)
Taxonomic note S. rostrata is said to be sold in Europe under the name S. gemmata, a synonym of S. sinensis.
Stewartia rostrata was recognised as distinct only in the early 1970s when Stephen Spongberg realised that two distinct entities were growing in the Arnold Arboretum under the name S. sinensis. The confusion was traced back to the mixed collections made in Jiangxi Province in 1907 by E.H. Wilson under W 1722, which both contributed to Rehder and Wilson’s description of S. sinensis (Spongberg 1974). The individual that prompted the investigation had been received from the Lushan Botanical Garden, Jiangxi in 1936, and probably represents the first introduction of the species: it is likely that much of the material in cultivation has been derived from this plant. Hsu, Boland & Camelbeke (2008) mention that it hybridises easily with other species, especially S. sinensis, so hybrids should be expected in seed-raised batches.
Bean (1981) stated that S. rostrata was not in cultivation in Britain, and Johnson (2011) reports it as scarce, with the tallest specimen recorded being 6 m tall at Grayswood Hill, Surrey in 2010. However it is currently freely available from nurseries in Europe and is grown in collections throughout the eastern United States: presumably it will become more familiar over time. Hsu, Boland & Camelbeke (2008) describe the bark as ‘unremarkable’ and ‘rather nondescript’ and say that seedlings can be slow to flower, reaching 8 m over 15 years without flowering – but there are compensations in the potentially scarlet autumn colour, and the red bracts and capsules. It’s also the earliest Stewartia to flower, starting in May.
Selected by Cees and Elly van Ostaayen from seedlings raised at their Hulsdonk nursery, Peer, Belgium. Flowers are a soft pink (though the depth of colour can vary with the season), and are produced on young plants (Hulsdonk).
Introduced by Broken Arrow Nursery in 2012, selected by Adam Wheeler from seedlings in a production field. Images show a clear pink corolla fading to white in the centre and at the base (A Way to Garden accessed July 2016).
A clone with irregular white sectors on the foliage, originating from Japan, is cultivated in France (A.D. Les Avettes pers. comm. July 2016).