Ulmus davidiana var. japonica 'Jacan'
|Ulmus davidiana var. japonica|
'Jacan', Sir Harold Hillier Gardens, UK
Pests and diseases
The tree is moderately resistant to Dutch elm disease, and elm leaf beetle Xanthogaleruca luteola . The tree's foliage was adjudged "resistant" to Black Spot by the Plant Diagnostic Clinic of the University of Missouri .
'Jacan' has not been widely planted in Canada owing to restrictions imposed by the Canadian government on the movement of elms across the country, which severely limited its potential market. The tree was introduced to the UK (see Accessions) and Italy from Canada in the early 1980s, but was never in commerce in either country and thus remains very rare; it is not known to have been introduced to Australasia.
'Jacan' was crossed with 'Sapporo Autumn Gold' by the Istituto per la Protezione delle Piante, Florence; the selection identified as 'FL441'. Although it performed well in trials, being noted for its abundant foliage, 'FL441' was never patented or released to commerce.  A specimen of 'FL441' is grown as part of Butterfly Conservation's elm trials at Great Fontley, Hampshire.
- North America
- Brighton & Hove City Council, UK, NCCPG National Elm Collection, UK champion: Sussex University campus, 15 m high, 31 cm d.b.h. in 2002, (listed as U. japonica 'Jacan').
- Sir Harold Hillier Gardens, UK. Acc. nos. 1981.0133, 1982.4002 (listed as U. japonica 'Jacan').
- North America
- Ronald, W. G. (1979). 'Jacan' Japanese Elm. Canadian Journal of Plant Science, 59, 267–268
- Heybroek, Hans M. (1981). "The Japanese elm species and their value for the Dutch elm breeding program" (PDF). Proceedings of the Dutch Elm Disease symposium and workshop, October 5–9, Winnipeg, Manitoba: 78–90.
- Burdekin, D. A. & Rushforth, K. D. (Revised by Webber J. F. 1996). Elms resistant to Dutch elm disease. Arboricultural Research Note 2/96. Arboricultural Advisory and Information Service, Alice Holt, Farnham, UK.
- Santini, A, et al. Elm breeding for DED resistance, the Italian clones and their wood properties. Invest. Agrar: Sist Recur For (2004) 13 (1), 179–184.
- Brookes, A. H. (2015). Great Fontley Elm Trial, 2015 Report. Butterfly Conservation, Hants & IoW Branch, England.
- Johnson, Owen (ed.) (2003). Champion Trees of Britain & Ireland. Whittet Press, ISBN 978-1-873580-61-5.