Hemiptelea davidii

Hemiptelea davidii is a small Chinese and Korean tree related to the elm, rarely grown in our gardens despite its easy cultivation. Extremely hardy and undemanding in terms of soil type, this species has the advantage of not being susceptible to Dutch elm disease, and the long spines that dot its bark are excellent for a defensive hedge. It will also please with its wide silhouette and its small toothed leaves that turn a beautiful yellow colour in autumn. A strange and endearing tree, worth discovering!

Hemiptelea davidii, known as Chinese Thorn-elm, belongs, like our field elm, to the family Ulmaceae. This small deciduous tree is native to China and Korea where it is valued for its hard wood, the fibre extracted from its bark, its leaves used as tea, and its seeds from which oil is extracted.

It is a moderately fast-growing small tree that can have multiple trunks, with a wide and spreading crown. Almost as wide as it is tall, it will reach an average of 6m (20 ft) in all directions, sometimes more (up to 10m (33 ft)) depending on the growing conditions. Its bark is dark grey to grey-brown, with fairly deep furrows on mature specimens, as well as spines measuring 2 to 10 cm (0.8 to 3.9 in) long. The branches are grey-brown to violet-brown, and downy. Its leaves are arranged alternately on the branches. They are elliptical to oblong-elliptical in shape, regularly toothed, and measure from 4 to 7 cm (1.5 to 3 in) long and 1.5 to 3 cm (0.6 to 1.2 in) wide. They change from light green in spring and summer to yellow in autumn before falling. Hemiptelea davidii produces inconspicuous flowers in April-May, at the axils of young leaves: it consists of clusters of small greenish flowers that will give rise to small winged fruits called samaras, initially greenish yellow, turning to a fairly dark brown at maturity in September-October.

Thorn-elm is an unpretentious and undemanding small tree that deserves to find its way into our gardens. It is also a useful plant for protecting a garden and sheltering native wildlife. It can be planted in a defensive hedge, kept informal or clipped, or planted in rows along countryside boundaries. Combine it with purple foliage such as that of the purple hazel 'Red Majestic' or the common hornbeam 'Purpurea'. A more informal and rustic setting will welcome it among the flamboyant autumn colours of small maples, deciduous euonymus, deciduous viburnums, the Orange Retz hornbeam, and Parrotia persica.