Plant 258

Thujopsis dolabrata (L.f.) Sieb. & Zucc. (Cupressaceae)


Thujopsis dolabrata was first described as Dolophyllum by Richard Anthony Salisbury in 1817, which was only (re)discovered in the early 1990s. Salisbury did not describe an accompanying species and therefore the name is unacceptable under the rules for plant naming. Furthermore, all publications since 1844 have used Thujopsis and the genus is widely known by that name. Therefore, the name Thujopsis has been conserved against Dolophyllum despite the latter being published earlier.

Endemic to Japan, Thujopsis dolabrata was first introduced to the United Kingdom in 1853 when Thomas Lobb sent a plant to Messrs Veitch of Exeter. The plant soon died but, in the 1850s, Captain Fortescue brought a plant from Japan that was grown at Castle Hill, Devon, and propagated by cuttings. Thujopsis is a valuable ornamental tree in its native Japan, and is commonly planted around temples as well as in gardens. However, it is confined to areas with good rainfall or in gardens with reliable irrigation, as the species is not drought tolerant.

The genus Thujopsis, which contains only one species, closely resembles Thuja (the Greek suffix opsis means 'resembling'), but differs from the latter in having broad, flat branches and larger leaves.

An important forest tree in Japan, Thujopsis was selected as one of the 'Five sacred trees of Kiso', originally preserved for imperial use in feudal times in ancient Japan. There are now managed state forests with this species as the dominant tree, besides some imperial forests. The tree's wood is used in construction, for buildings, lacquer work and woodcarvings. The species is a constituent of evergreen and evergreen-deciduous forests from lowland coastal areas to montane sites in regions with a cool, moist climate, and is commonly associated with the conifer Tsuga diversifolia.

A tree up to 30 metres tall in its native range, Thujopsis dolabrata, commonly known as Hiba arborvitae, is a dense, slow growing, pyramidal evergreen. In cultivation, mature trees typically reach about 15 metres in height. The hard, rigid leaves are borne in four ranks and are arranged in flattened branches that are held horizontally. The leaves of the lateral ranks are strongly ridged. The foliage is a lustrous, dark glossy to emerald green above, with conspicuous blur-green patches beneath. Thujopsis dolabrata is one of the most distinctive cupressaceous 'cedars', and is often divided into a northern variety called hondae, from Hokkaido and northern Honshu, and a more southern variety called dolabrata.

Further reading

Bean WJ 1976. Trees and shrubs hardy in the British Isles. Vol. 4. John Murray.

Farjon A 2005. A monograph of Cupressaceae and Sciadopitys. Royal Botanic Gardens, Kew.

Farjon A 2008. A natural history of conifers. Timber Press.

Ben Jones