Liquidambar acalycina H.T. Chang

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Credits

Owen Johnson (2021)

Recommended citation
Johnson, O. (2021), 'Liquidambar acalycina' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/liquidambar/liquidambar-acalycina/). Accessed 2021-09-27.

Common Names

  • Chang's Sweet-gum

Glossary

flush
Coordinated growth of leaves or flowers. Such new growth is often a different colour to mature foliage.
flush
Coordinated growth of leaves or flowers. Such new growth is often a different colour to mature foliage.
section
(sect.) Subdivision of a genus.

Credits

Owen Johnson (2021)

Recommended citation
Johnson, O. (2021), 'Liquidambar acalycina' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/liquidambar/liquidambar-acalycina/). Accessed 2021-09-27.

Tree to 25 m, often slender with a single axis. Bark smooth, grey, cracking into shallow rectangular plates after c. 30 years. Shoots glabrous and with numerous lenticels; buds pointed, mostly glabrous, many-scaled. Stipules 3–10 mm, brown-tomentose, or absent. Leaves 8–13 × 8–15 cm, 3-lobed (or 5-lobed on seedlings), the central lobe broadly ovate and lateral lobes triangular, margins serrate, apex finely elongated, somewhat caudate; leaves glabrescent; petiole 4–8 cm long. Male inflorescences globose, 2–2.5 cm wide, several arranged in a raceme, peduncle 2–3 cm long. Female inflorescences globose, solitary, with 15–26 flowers, peduncle 3–6 cm, sparsely pubescent. Female flowers with styles 5–7 mm long, brown and pubescent. Fruit a woody capsule, without long bristles between each seed. Flowering March to June, fruiting July to September (China). (Flora of China 2021).

Distribution  China Anhui, Guangdong, Guangxi, Guizhou, Hubei, Jiangsu, Jiangxi, Sichuan.

Habitat Largely evergreen montane forests, on often poorly drained sandstone, 600–1000 m asl.

USDA Hardiness Zone 6

RHS Hardiness Rating H6

Conservation status Not evaluated (NE)

Liquidambar acalycina was first differentiated from L. formosana by H.T. Chang in 1959, the latter being a tree with a much wider distribution across east Asia. Both species can be distinguished from the familiar American L. styraciflua by their leaves, which are a matt dark green with three rather shallow lobes, by their relatively modest stature in cultivation, and by their bark which is greyer and only cracks into ridges and knuckles in maturity. L. acalycina, however, can be readily told from L. formosana by its shorter leaf-stalks and its almost hairless winter shoots and buds. When conditions are warm enough for trees to fruit, the gum-balls of L. formosana are also distinct in their greater number of individual fruit and the slender bristles in between them, leading Hermann Harms in 1930 to segregate L. formosana in its own section of the genus, Cathayambar; nevertheless, a more recent genetic analysis (Hoey & Parks 1994) suggests that L. acalycina and L. formosana are more closely related to one another than either is to L. styraciflua. The two Chinese species can sometimes be found in the same areas, but in these cases L. acalycina will be confined to higher elevations (Hoey & Parks 1994); it is often found alongside Nyssa sinensis, one of the few other Chinese trees to show brilliant autumn colour in cultivation. It is the most genetically variable of the Liquidambar species studied by Hoey and Parks, its populations having long been isolated on various mountain ranges (Hoey & Parks 1994).

Deciduous trees from the mountains of southern China often show a red or purplish flush in spring, and when they are young and vigorous can continue to produce vivid new growths through summer; the colour results from anthocyanins, produced by the tree to protect the chemistry within the developing leaf from the high levels of solar radiation which these plants experience in their native habitat. In cultivation in northwest Europe, this colour persists, despite the much lower light levels, and it provides perhaps the most attractive feature of L. acalycina. For a few weeks in spring, the most striking forms can be wine red or even purple; at Furzey Gardens in Hampshire, where this tree is grown in numbers, a few individuals remain reddish in their outer crown throughout the growing season. In October, on this garden’s light acidic soils, the reddish purple returns, but autumn colour is unreliable in the United Kingdom and Ireland. In Vancouver, this feature is described as bright orange and purple (Wharton, Hine & Justice 2005) and is likeliest to be best in a more continental climate, sometimes persisting into December. The best trees are approximately conic in shape so far; like all Liquidambar, their wood is rather brittle, and early damage can lead to ugly forks or a multi-stemmed habit (which can always be corrected by formative pruning). The ultimate size can be expected to be similar to that of L. formosana, which is a medium-sized tree in the United Kingdom and Ireland, with a typically slender crown.

Liquidambar acalycina was introduced to the West by the Sino-American Botanical Expedition of 1980 – the first opportunity for many decades for American botanists to explore and collect seed from the vast wealth of native Chinese plants. Seedlings from this collection (SABE 1950, made in the ‘Metasequoia region’ of western Hubei) were quite widely distributed to institutions around the United Kingdom and the USA. The example in the Royal Botanic Gardens, Kew, was 12 m tall by 2011 (Tree Register 2021), while a younger accession planted by Carol Gurney at Higham Lodge in Suffolk – where summers can be very dry – had reached the same height by 2017 (Tree Register 2021). In the warmer growing season of the eastern United States, growth has been faster (Grimshaw & Bayton 2009), and the species succeeds at the Arnold Arboretum in Massachusetts, where L. formosana has proved too tender (Hsu & Andrews 2005). A young tree is also thriving at the Bratislava Botanic Garden in Slovenia (monumentaltrees.com 2021). In the United Kingdom, the apparent absence of specimens outside the warmer parts of southern England possibly says more about the conservative nature of most gardeners than it does about this particular species’s capacity to tolerate cooler summer conditions. Two cutting-raised plants were received from Westonbirt at the Royal Botanic Garden Edinburgh in 2015; planted in the vicinity of the Caledonian Hall, they have grown very slowly (T. Christian pers. comm. 2021).

Seed was also obtained by Wakehurst Place and Windsor Great Park from the Shanghai Botanic Garden in 1996 (Hsu & Andrews 2005), though these trees seem to show no autumn colour. As one of the very first ‘new trees’ to come out of China, L. acalycina has since become relatively widely grown in the United Kingdom. In recent years, Barcham Trees nursery has sold it at large standard size, and thriving young street plantings can now be seen in Canterbury and across Greater London (Tree Register 2021). It is one of very few trees from the mountains of China to have been tested in this role: all are used to wet and humid summers and so can find urban conditions challenging. Along with Wollemia nobilis, Chang’s Sweet-gum is also perhaps the only recently introduced tree species to have attained such a widespread level of prominence. The species is also sold in New Zealand by Greenleaf Nurseries, for example.

Scions from the good specimen at the late Peter Chappell’s garden, Spinners in Hampshire, have been distributed under the clonal name ‘Spinners’, while the selection ‘Burgundy Flush’ is also now popular enough in the United Kingdom and the United States to merit its own entry on this site. It is no longer possible to trace the wild origins of all the L. acalycina in cultivation (Grimshaw & Bayton 2009), but, as a species with considerable natural genetic diversity, any new introductions should still be welcomed and diligently recorded.


'Burgundy Flush'

Awards
AGM

A clone selected for the rich, dark colour of its spring flush; the growth tips of a young and vigorous specimen will remain reddish purple through summer. Autumn colour (in the best conditions) is also reddish purple (Hsu & Andrews 2005). It is now available in the United States and the Czech Republic as well as in the UK and the Netherlands.


'Spinners'

Scions of the late Peter Chappell’s tree at Spinners garden and nursery in Hampshire are now sold under this name (while the garden itself, slightly confusingly, was named after the unrelated Spinning Gum, Eucalyptus perriniana, which once grew there). The original ‘Spinners’, whose new leaves flush purplish throughout summer, enjoy an ideal, acidic soil with woodland shelter, and its good form and particularly long-lasting autumn colour (Pan-Global Plants 2021) may not be matched by examples of this clone planted in less congenial conditions.