The

American Elm ''Ulmus americana'', generally known as the American elm or, less commonly, as the white elm or water elm, is a species of elm native to eastern North America. The trees can live for several hundred years. It is a very hardy species that can ...

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

''Ulmus americana'' 'Delaware' was originally selected (as tree number 218, a c.1940 seedling from North Dakota) from 35,000 seedlings inoculated with the Dutch elm disease fungus in

USDA The United States Department of Agriculture (USDA) is an United States federal executive departments, executive department of the Federal government of the United States, United States federal government that aims to meet the needs of commerc ...

trials at Morristown,

New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...

Description

The tree has a relatively low stature and "undesirable" branching habit.Townsend, A. M., Bentz, S. E., and Douglass L. W. (2005)
Evaluation of 19 American Elm Clones for Tolerance to Dutch Elm Disease
''Journal of Environmental Horticulture'', March 2005, Horticultural Research Institute, Washington, D.C.

Pests and diseases

Further disease-resistance trials were conducted by both the USDA and the

United States National Arboretum The United States National Arboretum is an arboretum in northeast Washington, D.C., operated by the United States Department of Agriculture's Agricultural Research Service. It was established in 1927 by an act of Congress after a campaign by USDA ...

which confirmed the clone had a fair level of resistance to Dutch elm disease. 'Delaware' is susceptible to Elm Yellows, but resistant to 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 ...

''.

Cultivation

The original tree, which had been moved to the

National Arboretum,

Washington, D. C. Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and federal district of the United States. The city is on the Potomac River, across from Virginia, and shares land borders with ...

in 1948, died from unknown causes (probably elm yellows, by some accounts) in 1980, but a clone survives at the

Denver Botanic Gardens The Denver Botanic Gardens is a public botanical garden located in the Cheesman Park neighborhood of Denver, Colorado. The park contains a conservatory, a variety of theme gardens and a sunken amphitheater, which hosts various concerts in the ...

, as 'Delaware II'. Seven specimens stand in the

National Mall The National Mall is a Landscape architecture, landscaped park near the Downtown, Washington, D.C., downtown area of Washington, D.C., the capital city of the United States. It contains and borders a number of museums of the Smithsonian Institu ...

area, Washington D.C.Pruned 'Delaware', National Museum of Natural History, Constitution Avenue NW, Washington DC - Google Maps, August 2022, access date: 17 October 2022
/ref> Although propagated for further trials, the tree was never commercially released owing to its poor shape. 'Delaware' is not known to have been introduced to

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

Australasia Australasia is a subregion of Oceania, comprising Australia, New Zealand (overlapping with Polynesia), and sometimes including New Guinea and surrounding islands (overlapping with Melanesia). The term is used in a number of different context ...

. File:Washington Road Elm Allée (east side).jpg, Mature 'Princeton' elms on right, planted 1920s; 'Delaware' on left, planted in 1983, in a side allée of the Washington Road Elm Allée,

Princeton, New Jersey The Municipality of Princeton is a Borough (New Jersey), borough in Mercer County, New Jersey, United States. It was established on January 1, 2013, through the consolidation of the Borough of Princeton, New Jersey, Borough of Princeton and Pri ...

, US (2011)

Synonymy

*'Delaware II'. NB 'Delaware I' is the original name given to the hybrid 'Urban' before its commercial release.

Accessions

North America

Brooklyn Botanic Garden Brooklyn Botanic Garden (BBG) is a botanical garden in the Borough (New York City), borough of Brooklyn in New York City. The botanical garden occupies in central Brooklyn, close to Mount Prospect Park, Prospect Park (Brooklyn), Prospect Park, ...

, New York City, New York, US. Acc. no. 980489. *

Dawes Arboretum The Dawes Arboretum is a nonprofit arboretum located in Newark, Ohio. It includes nearly of plant collections, gardens and natural areas. The site includes approximately 12 miles (19 km) of hiking trails and roadways for a four-mile (6&nb ...

, US

Newark, Ohio, Newark,

Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...

, US. 1 tree, listed as 'Delaware #2'; no acc. details available. *

, US. No details available. *

Dominion Arboretum The Dominion Arboretum () is an arboretum part of the Central Experimental Farm of Agriculture and Agri-Food Canada in Ottawa, Ontario, Canada. Originally begun in 1889, the Arboretum covers about of rolling land between Prince of Wales Drive, ...

, Canada

No details available.

References

{{DEFAULTSORT:Ulmus Americana 'Delaware' American elm cultivar Ulmus articles with images Ulmus