Carpinus japonica Blume

Whilst Carpinus is a taxonomically difficult genus, the four ‘false hornbeams’ in Section Distegocarpus are comparatively easy to learn and make quite showy, memorable trees. Carpinus japonica has slightly less numerous lateral veins than the central Chinese C. fangiana and the leaf-base is less consistently heart-shaped than in the Taiwanese C. rankanensis or in C. cordata, which also grows in Japan but is not endemic to that country; most of the C. japonica’s synonyms result from the uncertain placing of Distegocarpus relative to Section Carpinus (Dong et al. 2022). The many lateral veins, neatly parallel and deeply impressed, the scaly bark, and the hop-like clusters of fruit with their whitish bracts are features shared by Section Distegocarpus and by the related genus Ostrya.

Carpinus japonica is one of the hardiest of its group and seems easy to grow, though like its closest allies it lacks the (potentially) bright autumn colours shown by most ‘true hornbeams’ (Dirr 2009). It was in Europe by 1895, when two were planted at the Royal Botanic Gardens, Kew (Bean 1976); one of these survived until 1981 when it was 9 m tall (Tree Register 2022). This is a more reliably arborescent plant than C. cordata, reaching 15 m × 36 cm dbh by 2012 at the National Botanic Gardens, Glasnevin in Dublin (Tree Register 2022). The species is now quite widely offered in the UK (Royal Horticultural Society 2020), and is one of the first oriental hornbeams to become available at large standard size for municipal use; by 2022 pleached specimens were offered as an alternative to the use of the native C. betulus within hornbeam allées (Majestic Trees 2022). Crûg Farm offers seedlings from BSWJ 10803 and BSWJ 11072 (Crûg Farm Plants 2020).

The species has survived at the Linnaeus Garden at Uppsala, Sweden since 2001 (Royal Botanic Garden Edinburgh 2022), and more recently at Arboretum Mustila in Finland (Arboretum Mustila 2022). It is also cultivated at the Dominion Arboretum in Ottawa, Canada (USDA hardiness zone 5a) (Stewart 2010). In the hot humid summers of the south-eastern United States it does best in some shade (Dirr 2009). This is one of rather few hornbeams to be offered in New Zealand (Leafland Wholesale Tree Nursery 2022).