A small to medium-sized deciduous, semi-deciduous (rarely semi-evergreen) tree growing to 10-18 m tall with a slender trunk and crown. The leathery, lustrous green single-toothed leaves are small, 2-5 cm long by 1-3 cm broad, and often retained as late as December or even January in Europe and North America. The flowers are produced in early autumn, small and inconspicuous, with the seed maturing rapidly and dispersing by late autumn. The trunk has a handsome, flaking bark of mottled greys with tans and reds, giving rise to its other common name, the Lacebark Elm, although scarring from major branch loss can lead to large canker-like wounds.[2][3][4][5]
Cultivation
The tree is arguably the most ubiquitous of the elms, now found in all the continents except Antarctica. Of considerable horticultural merit, it was described by Hilliers as "one of the most splendid elms, having the poise of a graceful Nothofagus".[6] It was introduced to Europe at the end of the 18th century as an ornamental, and is found in many botanical gardens and arboreta. In the United States, it appeared in the middle of the 19th century, and has proved very popular in recent years as a replacement for American Elms killed by Dutch elm disease.
One of the tree's major distinctions is its resistance to insect attack. It was adjudged as having the best pest resistance of about 200 taxa evaluated in elm trials at the Sunshine Nursery, Oklahoma.[7] Moreover, U. parvifolia is one of the cold-hardiest of the Chinese species. In artificial freezing tests at the Morton Arboretum.[8] the LT50 (temp. at which 50% of tissues die) was found to be - 34 °C.
Uses
The Chinese Elm is a tough landscape tree, hardy enough for use in harsh planting situations such as parking lots, in small planters along streets and in plazas or patios. In New Zealand, it was found to be particularly suitable for windswept locations along the coast. Chinese Elms are frequently used in bonsai; they are considered a good choice for beginners owing to their high tolerance of pruning.
Invasive species
The tree can become invasive, notably in southern Africa, and is known as one of the 'Nasty Nine' in Namibia, where it was planted as a street tree in Windhoek. The Chinese Elm has also shown invasive species tendencies in some gardens in North America.[9]
Also U. '240' (U. minor var. minor × U. parvifolia) raised at Wageningen but never commercially released; a few specimens survive as part of the Brighton & Hove CC NCCPG Elm Collection at Stanmer Park, planted in 1965.
The Status of Elms in the Nursery Industry in 2000, by Warren, K., and Schmidt, J. Frank & Son Co. (2002).
References
^ Fu, L., Xin, Y. & Whittemore, A. (2002). Ulmaceae, in Wu, Z. & Raven, P. (eds) Flora of China, Vol. 5 (Ulmaceae through Basellaceae). Science Press, Beijing, and Missouri Botanical Garden Press, St. Louis, USA.http://flora.huh.harvard.edu/china/PDF/PDF05/Ulmus.pdf
^ Bean, W. J. (1981). Trees and shrubs hardy in Great Britain, 7th edition. Murray, London.
^ White, J & More, D. (2003). Trees of Britain & Northern Europe. Cassell's, London.
^ Shirazi, A. M. & Ware, G. H. (2004). Evaluation of New Elms from China for Cold Hardiness in Northern Latitudes. International Symposium on Asian Plant Diversity & Systematics 2004, Sakura, Japan.