''Ulmus'' 'Urban' is an American

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

elm Elms are deciduous and semi-deciduous trees comprising the flowering plant genus ''Ulmus'' in the plant family Ulmaceae. They are distributed over most of the Northern Hemisphere, inhabiting the temperate and tropical-montane regions of North ...

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, ...

selected from the progeny of a controlled crossing of the

Siberian Elm ''Ulmus pumila'', the Siberian elm, is a tree native to Asia. It is also known as the Asiatic elm and dwarf elm, but sometimes miscalled the 'Chinese Elm' (''Ulmus parvifolia''). ''U. pumila'' has been widely cultivated throughout Asia, Nor ...

Ulmus pumila ''Ulmus pumila'', the Siberian elm, is a tree native to Asia. It is also known as the Asiatic elm and dwarf elm, but sometimes miscalled the 'Chinese Elm' (''Ulmus parvifolia''). ''U. pumila'' has been widely cultivated throughout Asia, Nor ...

'' (female parent) with the Dutch clone '148' ( ''U. × hollandica'' 'Vegeta' × ''U. minor'' '28') in 1958 by Toru Arisumi of the

USDA The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of com ...

Columbus Columbus is a Latinized version of the Italian surname "''Colombo''". It most commonly refers to: * Christopher Columbus (1451-1506), the Italian explorer * Columbus, Ohio, capital of the U.S. state of Ohio Columbus may also refer to: Places ...

Ohio Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...

. Clone '148' had been sent to the US from the Netherlands in 1952 by Johanna Went, leader of the elm research team at the Willie Commelin Scholten Phytopathology Laboratory in Baarn.. Schippers, B & Roosje, G S (1997). Hundred years of history and the future of the Foundation ‘Willie Commelin Scholten Phytopathological Laboratory’. ''European Journal of Plant Pathology'', October 1997, Volume 103, Issue 7, 667–671.

Description

'Urban' is considered a poor ornamental, the tree possessed of stiff branching and amorphous form. The

lanceolate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...

obovate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...

leaves are < 9 cm long × < 4 cm broad, smooth with light venation on the upper surface, on 6 mm petioles and clustered on short, very thin, wingless branchlets. Image: Urban foliage.JPG, Leaves and £1 coin Image: Urban bark.JPG, Bark of mature tree File:cathedral - regal - pioneer - urban - laevis - den haag.jpg, Elm cultivars, Nether-lands; 'Urban' 3rd from right

Pests and diseases

'Urban' has a moderate resistance to

Dutch elm disease Dutch elm disease (DED) is caused by a member of the sac fungi (Ascomycota) affecting elm trees, and is spread by elm bark beetles. Although believed to be originally native to Asia, the disease was accidentally introduced into Americas, America ...

; in trials conducted by the

Istituto per la Protezione delle Piante The Istituto per la Protezione delle Piante (IPP), or 'Institute of Plant Protection', is part of the Food Department of the Consiglio Nazionale delle Ricerche (CNR; "Italian National Research Council"), an Italian government organization with the a ...

, Florence, it suffered 49.5% defoliation and 36.5% dieback when inoculated with spores of the causal fungus, compared with 2.8% and 1.2% resp. for 'Sapporo Autumn Gold'.Santini, A, et al. (2002). 'San Zanobi' and 'Plinio' Elm trees. ''HortScience'' 37(7): 1139–1141, 2002. Foliage was adjudged "resistant" to Black Spot by the Plant Diagnostic Clinic of the

University of Missouri The University of Missouri (Mizzou, MU, or Missouri) is a public university, public Land-grant university, land-grant research university in Columbia, Missouri. It is Missouri's largest university and the flagship of the four-campus Universit ...

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However, foliage can be heavily to severely damaged by the Elm Leaf Beetle ''

Xanthogaleruca luteola ''Xanthogaleruca luteola'', commonly known as the elm-leaf beetle, is a beetle species in the family Chrysomelidae that is native to Europe but invasive in other parts of the world.http://cisr.ucr.edu/elm_leaf_beetle.html - Center for Invasive Sp ...

'' 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, 1976Ecker, M. E. (1997). Field Notes: Ulmus 'Urban'. ''American Nurseryman'', Jan. 1. 1997.

Chicago (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ...

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 The Forestry Commission is a non-ministerial government department responsible for the management of publicly owned forests and the regulation of both public and private forestry in England. The Forestry Commission was previously also respon ...

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 showgroun

south of

Shepton Mallet Shepton Mallet is a market town and civil parish in the Mendip District of Somerset, England, some south-west of Bath, south of Bristol and east of Wells. It had an estimated population of 10,810 in 2019. Mendip District Council is based t ...

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All these trees initially grew strongly on the heavy clay loam, attaining > 8 m in height in seven years. However, at this age, one died of

Dutch Elm Disease Dutch elm disease (DED) is caused by a member of the sac fungi (Ascomycota) affecting elm trees, and is spread by elm bark beetles. Although believed to be originally native to Asia, the disease was accidentally introduced into Americas, America ...

whilst four others exhibited weakness at the root and fell in gales in later years.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 Only one tree remains (the TROBI champion); 12 m high, 26 cm

d.b.h. Diameter at breast height, or DBH, is a standard method of expressing the diameter of the trunk or bole of a standing tree. DBH is one of the most common dendrometric measurements. Tree trunks are measured at the height of an adult's breast, ...

in 1997,Johnson, Owen (ed.) (2003). ''Champion Trees of Britain & Ireland''. Whittet Press, . and that in poor health in 2008. However, the trees are survived by numerous root suckers. Other plantings in Europe are few and far between; several were established in the port area of

Amsterdam Amsterdam ( , , , lit. ''The Dam on the River Amstel'') is the Capital of the Netherlands, capital and Municipalities of the Netherlands, most populous city of the Netherlands, with The Hague being the seat of government. It has a population ...

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The tree also featured in trial

in

Canberra Canberra ( ) is the capital city of Australia. Founded following the federation of the colonies of Australia as the seat of government for the new nation, it is Australia's largest inland city and the eighth-largest city overall. The ci ...

, 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 Japanese elm is a common name for several plants and may refer to: * ''Ulmus davidiana'' var. ''japonica'' *''Zelkova serrata ''Zelkova serrata'' (Japanese zelkova, Japanese elm or keyaki or keaki; ja, 欅 (ケヤキ) keyaki /槻 (ツキ) tsu ...

''U. davidiana'' var. ''japonica'') cultivar 'Prospector' to create the cultivar 'Patriot'.

Synonymy

*'Delaware No. 1': USDA, before commercial release as 'Urban'. *'Ohio Hybrid':

Accessions

;North America *

Chicago Botanic Garden The Chicago Botanic Garden is a living plant museum situated on nine islands in the Cook County Forest Preserves. It features 27 display gardens in four natural habitats: McDonald Woods, Dixon Prairie, Skokie River Corridor, and Lakes and Shore ...

, US. 1 tree, in West Collections Area, listed as ''U. × hollandica'' 'Urban'. *

Morton Arboretum The Morton Arboretum, in Lisle, Illinois, United States, is a public garden, and outdoor museum with a library, herbarium, and program in tree research including the Center for Tree Science. Its grounds, covering 1,700 acres (6.9 square kilometres ...

, US. Acc. no. 66–70 ;Europe *

Grange Farm Arboretum The Grange Farm Arboretum is a small private arboretum comprising 3 hectares accommodating over 800 trees, mostly native and ornamental species or cultivars, notably oaks, ashes, walnuts and elms, growing on a calcareous loam.Ostler, J. (2009) ' ...

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Lincolnshire Lincolnshire (abbreviated Lincs.) is a county in the East Midlands of England, with a long coastline on the North Sea to the east. It borders Norfolk to the south-east, Cambridgeshire to the south, Rutland to the south-west, Leicestershire ...

, UK. Acc. no. 824. *Wijdemeren City Council, Netherlands. Elm collection, used in elm trials Ankeveen 2014.

Nurseries

;North America *J. Frank Schmidt & Son Co

Boring, Oregon Boring is an unincorporated community in Clackamas County, Oregon, United States. It is located along Oregon Route 212 in the foothills of the Cascade mountain range, approximately southeast of downtown Portland, and northeast of Oregon City. ...

, US. *Lake County Nurser

Perry, Ohio Perry is a village in Lake County, Ohio, United States. The population was 1,663 at the 2010 census. History It is named in honor of Commodore Oliver Hazard Perry to commemorate his victory over the British fleet at the Battle of Lake Erie in ...

, US. *Sun Valley Garden Centr

Eden Prairie Eden Prairie is a city southwest of downtown Minneapolis in Hennepin County and the 16th-largest city in the State of Minnesota, United States. As of the 2020 census, it has a population of 64,198. The city is adjacent to the north bank of th ...

Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over to ...

, US.

References

{{Elm species, varieties, hybrids, hybrid cultivars and species cultivars , state=collapsed Hybrid elm cultivar Ulmus articles with images Ulmus