Ulmus 'Urban'

Infobox Cultivar | name = "Ulmus" hybrid


image_caption = 'Urban', Bath & West showground, Shepton Mallet, UK
hybrid = "U. pumila" × ('Commelin' × ("U. pumila" × 'Hoersholmiensis'))
cultivar = 'Urban'
origin = USA

'Urban' is an American hybrid elm cultivar derived from the same ancestry as 'Homestead' and 'Regal', comprising the Siberian Elm "Ulmus pumila", the early Dutch hybrid 'Commelin', and a Danish field elm cultivar "Ulmus minor" 'Hoersholmiensis', and selected from progeny of a controlled crossing made in 1958 by Toru Arisumi of the USDA at Columbus, Ohio.

Description

Considered a poor ornamental, the tree is possessed of stiff branching and amorphous rounded form. The lanceolate to obovate leaves are < 90 mm long by 40 mm broad, smooth with light venation on the upper surface, on 6 mm petioles and clustered on short, very thin, wingless branchlets.

Pests and diseases

'Urban' has a moderate resistance to Dutch elm disease, but can be heavily to severely damaged by the Elm Leaf Beetle "Xanthogaleruca luteola" [http://www.sunshinenursery.com/survey.htm] Bean, W. J. (1980). "Trees and shrubs hardy in Great Britain", 8th edition. Murray, UK.] Schreiber, L. R. & Main, H. V. (1976). "HortScience", 11: 517-518, 1976] Ecker, M. E. (1997). Field Notes: Ulmus 'Urban'. "American Nurseryman", Jan. 1. 1997. Chicago.]

Cultivation

Noted for its tolerance of poor soils, pollution, and drought, 'Urban' was one of a number of elm hybrids assessed by the Forestry Commission in the UK in the 1970s; half a dozen trees were among a batch of elms donated by the Commission in 1981 to reinforce a shelter belt at the Royal Bath & West showground [http://www.streetmap.co.uk/newmap.srf?x=362500&y=139500&z=3&sv=362500,139500&st=4&ar=N&mapp=newmap.srf&searchp=newsearch.srf&dn=716] south of Shepton Mallet [http://www.streetmap.co.uk/newmap.srf?x=363080&y=140120&z=5&sv=363080,140120&st=4&ar=Y&mapp=newmap.srf&searchp=newsearch.srf&dn=716] . All the trees initially grew strongly on the heavy clay loam, attaining over 8 m in height in seven years. However, at this age, one died of Dutch Elm Disease whilst four others exhibited weakness at the root and fell in gales in later years; only one remains (the UK champion), and that in poor health in 2008 Rouse, G. D. (1989). Elms on the Royal Bath & West Showground. "Quarterly Journal of Forestry" 83. 170-172, 1989. Royal Forestry Society, Tring, Herts., UK] . The trees are survived by numerous root suckers however.

Other plantings in Europe are few and far between; several were established in the port area of Amsterdam [http://www.amsterdambomen.nl] . The tree also featured in trials [http://www.netspace.net.au/~stephenf/Resistant_Elms.html] , in
Canberra, Australia started in 1988 but "has not shown promise in that environment".

Hybrid cultivars

'Urban' was crossed with the Wilson's Elm (now treated as Japanese Elm "U. davidiana" var. "japonica") cultivar 'Prospector' to create the cultivar 'Patriot'.

ynonymy

*'Delaware No. 1': USDA, before commercial release as 'Urban'.
*'Ohio Hybrid': Santamour, F. S., & Bentz, S. E. Updated checklist of elm (Ulmus) cultivars for use in North America. "Journal of Arboriculture", 21(3): May, 1995.

Accessions

;North America
*Chicago Botanic Garden, Glencoe, Illinois. 1 tree, in West Collections Area, listed as "U. × hollandica" 'Urban'.
*Morton Arboretum acc. no. 66-70 ;Europe
*Brighton & Hove City Council, NCCPG elm collection [http://www.brighton-hove.gov.uk/index.cfm?request=c1108042] .
*Royal Bath & West Showground, Somerset. UK champion, 12 m high, 26 cm d.b.h. in 1997 Johnson, Owen (ed.) (2003). "Champion Trees of Britain & Ireland". Whittet Press, ISBN 9781873580615.] .

Nurseries

;North America
*J. Frank Schmidt & Son Co. [http://www.jfschmidt.com/index.html] , Boring, Oregon
*Lake County Nursery [http://www.lakecountynursery.com/] , Perry, Ohio.

References