Ostrya japonica Sarg.

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Claire Mansel Lewis

Credits

Owen Johnson (2022)

Recommended citation
Johnson, O. (2022), 'Ostrya japonica' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/ostrya/ostrya-japonica/). Accessed 2022-08-17.

Genus

Common Names

  • Japanese Hop-hornbeam

Synonyms

  • Ostrya liana Hu

Glossary

USDA
United States Department of Agriculture.
dbh
Diameter (of trunk) at breast height. Breast height is defined as 4.5 feet (1.37 m) above the ground.

Credits

Owen Johnson (2022)

Recommended citation
Johnson, O. (2022), 'Ostrya japonica' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/ostrya/ostrya-japonica/). Accessed 2022-08-17.

Tree to 20 m tall; bark dark grey-brown, soon cracking into long narrow scales. Twigs grey-brown, velvety at first (the hairs often glandular). Leaf 4–12 × 2–5 cm, velvety above at first and remaining so beneath, especially under the veins, and with axillary tufts; lateral veins in 10–15 pairs, not very closely parallel (c. 5–10 mm apart); margin irregularly double-serrate; petiole 10–15 mm long, velvety, the hairs often glandular. Fruiting catkin short (15–25 mm), on a velvety 20–25 mm peduncle; bladders 1–2 cm long, glabrescent; nutlet 6–7 mm long, glabrous. (Li & Skvortsov 1999).

Distribution  China S Gansu, Hebei, Henan, Hubei, Shaanxi, Sichuan JapanSouth Korea And perhaps in North Korea

Habitat Forests; to 2800 m asl in the south of the range.

USDA Hardiness Zone 5

RHS Hardiness Rating H6

Conservation status Least concern (LC)

Seed of Ostrya japonica was first sent from Japan – where it is a rather scarce but widespread tree – to the Arnold Arboretum in Massachusetts by Heinrich Mayr in 1888 (Dosmann 2017; Elwes & Henry 1906–1913); the original tree (1888.3359*A) still survived in the Arboretum in 2022. The species reached the Royal Botanic Gardens at Kew, from the same source, in 1897 (Bean 1976), though both the original plants here have long gone (Tree Register 2022); in 2022 it was represented at Kew by a very bushy 11-metre plant from EHOK 130, and this same collection also grows at Dawyck Botanic Garden in Scotland (Royal Botanic Garden Edinburgh 2022). The potentially diverse populations from mainland east Asia may never have been introduced to the west. In the climate of north-west Europe this may not be a long-lived species; a fine 1910 planting at Borde Hill in West Sussex was standing dead one hundred years later (Tree Register 2022). The largest surviving example may be one in the Winter Garden at the Sir Harold Hillier Gardens, 11 m × 53 cm dbh in 2011 (Tree Register 2022).

The Japanese hop-hornbeam has slightly fewer and less markedly parallel pairs of leaf-veins than O. carpinifolia, though the leaf can be at least as large; young plants in collections – before the characteristically scaly bark begins to develop – can look remarkably like Carpinus betulus, except when carrying their hop-like fruit-clusters. These clusters are unusually short, and so not quite as showy than the European tree’s. The foliage also tends to be particularly downy; the short velvety hairs on the twig and leaf-stalk are characteristically tipped by a microscopic gland.

In the UK this remains a scarce collector’s plant, advertised by only one specialist nursery in the 2020 RHS Plant Finder (Royal Horticultural Society 2020). However, like most of its genus it seems an easy tree to grow, and is very hardy; it has been cultivated since 1949 at the Linnaeus Garden of Uppsala University in southern Sweden (Royal Botanic Garden Edinburgh 2022). At the Dominion Arboretum in Ottawa, Canada (USDA hardiness zone 4b) it survives but is cut back in hard winters, and remains a shrub (Stewart 2010). It is also bushy in the long hot summers of the JC Raulston Arboretum in North Carolina (Dirr 2009).