Ulmus glabra 'Exoniensis'
Ulmus glabra 'Exoniensis', the 'Exeter Elm', was discovered near Exeter, England, in 1826, and propagated by the Ford nursery in that city.[1][2][3][4] Its fastigiate shape when young, upward-curving tracery, small samarae and leaves, late leaf-flush and late leaf-fall, taken with its south-west England provenance, suggest a link with the Cornish Elm Ulmus minor subsp. angustifolia, which shares these characteristics.
Description
The tree initially has an upright, columnar form,[5] but later develops a large rounded crown and occasionally reaches 17 m in height. It is chiefly distinguished by its contorted leaves, < 11 cm long by 8 cm broad, which occasionally wrap around the branchlets and remain attached to the tree well into winter. 'Exoniensis' comes into leaf later than U. glabra and U. glabra sports such as 'Camperdownii' and 'Horizontalis',[6] and keeps its foliage longer. Unlike 'Camperdownii' and 'Horizontalis', it does not produce large U. glabra-type samarae.
Pests and diseases
'Exoniensis' possesses a moderate resistance to Dutch elm disease, and is consequently often featured in the Dutch elm breeding programme in association with the Field Elm U. minor and Himalayan Elm U. wallichiana.[7]
Cultivation
Once commonly planted in the UK and parts of western Europe, 'Exoniensis' is also known to have been marketed in Poland in the 19th century by the Ulrich nursery,[8] Warsaw, and may still survive in Eastern Europe. In Sweden it is sometimes pruned from an early age to form a tidy cone-shaped tree called locally 'pyramidalm' (: pyramid elm).[9] It is found in Australia at Ballarat but is not known to have been introduced to North America.
Notable trees
A 180 year-old specimen in Hamburg has attained a height of 28m and a trunk diameter of 1.45m.[10] The TROBI UK Champion is at Preston House, West Lothian, Scotland, measuring 22m high, 115 cm d.b.h. in 1987. Three mature trees grow at Bruntsfield Links and three (2010) in Lomond Park, Edinburgh. The cultivar is represented in Éire by a tree at Birr Castle (Mount Palmer), County Offaly, with a d.b.h. of 29 cm when measured in 2002.
Hybrid cultivars
'Clusius', 'Columella, 'Dodoens', 'Lobel', 'Plantyn', 'Nanguen' (Lutece), 'Wanoux' (Vada).
'Exoniensis' also indirectly featured in the Italian elm breeding programme as an ancestor of 'Plantyn', which was commonly crossed with clones of the Siberian Elm Ulmus pumila to produce the cultivars 'Arno', 'Plinio', and 'San Zanobi'.[11][12]
Synonymy
- Ulmus campestris var. nuda subvar. fastigiata oxfortii Hort. Vilv., probable misspelling.
- Ulmus fordii Hort.: Loudon, Arb. Frut. Brit. 3: 1399, 1838.
- Ulmus montana fastigiata: Loudon, Arb. Frut. Brit. 3: 1399, 1838.
- Ulmus montana f. fastigiata plumosa Hort.: Schelle in Beissner et al. Handb. Laubh. Benenn, 85, 1903.
- Ulmus ontariensis Hort. ex. Steud.
- Ulmus plumosa: C. de Vos [8], Woordenbeck, 136, 1867.
- Ulmus plumosa foliis variegatis: C. de Vos, Woordenboek 137, 1867.
- Ulmus suberosa oxoniensis: Audibert, Tonelle, Tarascon, France Catalogue, 1832, probable misspelling.
- Ulmus ? var. replicata: Masters, Hort. Duroverni, 67, 1831, name in synonymy.
Accessions
- Europe
- Arboretum Trompenburg [9], Netherlands. No details available.
- Brighton & Hove City Council, UK, NCCPG elm collection [10]. Small number of trees, large specimens at Stanmer Park Arboretum, St. Roche's Arboretum, Dumbrell Court, Linkway Lodge.
- Cambridge Botanic Garden [11], University of Cambridge, UK. 1 tree, no accession details available.
- Dubrava Arboretum, Lithuania. No details available.
- Grange Farm Arboretum [12], Sutton St. James, Spalding, Lincs., UK. Acc. no. 829.
- Hortus Botanicus Nationalis, Salaspils, Latvia. Acc. nos. 18105,6,7.
- Linnaean Gardens of Uppsala, Sweden. Acc. no. 0000-1006.
- Royal Botanic Garden Edinburgh, UK. Acc. no. 19699363.
- Sir Harold Hillier Gardens, UK. Acc. nos. 1977.6756, 1977.7086.
- Tallinn Botanic Garden, Estonia [13]. No accession details available.
- University of Copenhagen, Botanic Garden Denmark. No details available.
Nurseries
Europe
- Arboretum Waasland [14], Nieuwkerken-Waas, Belgium.
- Hollybush Nursery [15], Hollybush Cottage, Slaley, Hexham, Northumberland, UK.
- PlantenTuin Esveld [16], Boskoop, Netherlands.
- Standard Trees [17], Golden Cross, East Sussex, UK
- Thornhayes Nursery [18], Cullompton, Devon, UK
- Westerveld Boomkwekerij B.V.[19], Opheusden, The Netherlands.
References
- ^ Bean, W. J. (1981). Trees and shrubs hardy in Great Britain, 7th edition. Murray, London
- ^ Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. pp 1848-1929. Private publication, Edinburgh. [1]
- ^ Richens, R. H. (1983). Elm. Cambridge University Press.
- ^ White, J. & More, D. (2003). Trees of Britain and Northern Europe. Cassell's, London.
- ^ Photograph of fastigiate form of young Exeter elm, [2]
- ^ Photograph of 'Exoniensis' leaves in early summer [3]
- ^ Heybroek, H. (1983). The Dutch elm breeding program. In Sticklen & Sherald (Eds). Dutch elm disease research (Ch. 3). Springer Verlag, New York.
- ^ Ulrich, C. (1894), Katalog Drzew i Krezewow, C. Ulrich, Rok 1893-94, Warszawa
- ^ Photographs of 'Pyramidalm' and unpruned 'Exoniensis' in Sweden, www.tradgardsakademin.se [4]
- ^ U. glabra 'Exoniensis', the "Planten un Blomen", Hamburg: from the Handbuch der Ulmengewächse, [5] (picture 2)
- ^ Santini A., Fagnani A., Ferrini F. & Mittempergher L., (2002) 'San Zanobi' and 'Plinio' elm trees. [6] HortScience 37(7): 1139-1141. 2002. American Society for Horticultural Science, Alexandria, VA 22314, USA.
- ^ Santini A., Fagnani A., Ferrini F., Mittempergher L., Brunetti M., Crivellaro A., Macchioni N., Elm breeding for DED resistance, the Italian clones and their wood properties. [7] Invest Agrar: Sist. Recur. For. (2004) 13 (1), 179-184. 2004