''Ulmus'' 'Morton Stalwart' (selling name ), is a Morton Arboretum

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 ...

cultivar arising from a controlled crossing of with the hybrid of a Field Elm ''U. minor'' from eastern Russia and a Siberian Elm ''U. pumila''.Morton Arboretum Commendation Elm
/ref> Tested in the US National Elm Trial coordinated by

Colorado State University Colorado State University (Colorado State or CSU) is a public land-grant research university in Fort Collins, Colorado. It is the flagship university of the Colorado State University System. Colorado State University is classified among "R1: ...

, averaged a survival rate of 85% after 10 years.

Description

The branches are upright, but the form of the tree is more oval than vase-shaped; the leaves are relatively large. However, examples grown in the warmer climes of the southern United States have not impressed, and it was dismissed, along with its Morton stablemates and , as 'ugly' by

Michael Dirr Michael A. Dirr, Ph.D is a horticulturist and a professor of horticulture at the University of Georgia. He is an expert on woody plants. Education and experience Dirr earned a Bachelors in Science degree in Plant Physiology and a Masters in Science ...

, Professor of Horticulture at the University of Georgiabr>
on account of its 'wild' growth and splaying branches.

Pests and diseases

Although resistant to Dutch elm disease in the United States, the tree is moderately susceptible to insects, notably elm leaf beetle '' Xanthogaleruca luteola'',McPherson, G. et al. (2008). National elm trial: Initial report from Northern California. ''Western Arborist'', Fall 2009, 32–36. Japanese beetleBrady, C., Condra, J., & Potter, D. (2008) Resistance of Landscape-suitable Elm (Ulmus spp.) Cultivars to Japanese Beetle, Leaf Miners, and Gall Makers. ''2008 Research Report, Nursery & Landscape Program'', 15–16. University of Kentucky. and Gypsy moth.

Cultivation

is vigorous and robust, adjudged the third fastest-growing cultivar of 17 assessed by the University of Minnesota and fourth out of 15 in trials at U C Davis. The tree is also extremely tolerant of droughtGiblin, C. P. & Gillman, J. H. (2006). ''Elms for the Twin Cities: A Guide for Selection and Maintenance.'' University of Minnesota. and cold; in artificial freezing tests at the Morton ArboretumShirazi, A. M. & Ware, G. H. (2004). ''Evaluation of New Elms from China for Cold Hardiness in Northern Latitudes''. International Symposium on Asian Plant Diversity & Systematics 2004,

Sakura A cherry blossom, also known as Japanese cherry or sakura, is a flower of many trees of Prunus, genus ''Prunus'' or Prunus subg. Cerasus, ''Prunus'' subg. ''Cerasus''. They are common species in East Asia, including China, Korea and especia ...

, Japan. the tree was found cold-hardy to −40° C. was introduced by Chicagoland Grows and is currently being evaluated in the

National Elm Trial The National Elm Trial was an American volunteer effort to evaluate a range of newly developed elm cultivars as replacements for elms destroyed by Dutch elm disease. The Colorado State University College of Agricultural Sciences coordinated the tri ...

CSU Shade Tree Lab
coordinated by

. The tree was introduced to the UK in 2014, but is not known (2016) to have been introduced to Australasia. File:190908 179 Chicago Botanic Gdn - Esplanade, North Lake, Ulmus 'Morton Stalwart' Commendation™ Elm (48861571041).jpg, ''Ulmus'' 'Morton Stalwart' Commendation™, Esplanade, North Lake, Chicago Botanic Garden (September 2019) File:CBG Esplanade - view of North Lake, Ulmus 'Morton Stalwart' Commendation 150627 (19713630363).jpg, Boles of 'Morton Stalwart' Commendation™

Accessions

;North America *

Arnold Arboretum The Arnold Arboretum of Harvard University is a botanical research institution and free public park, located in the Jamaica Plain and Roslindale neighborhoods of Boston, Massachusetts. Established in 1872, it is the oldest public arboretum in N ...

, US. Acc. no. 131–2002 *

Bickelhaupt Arboretum Bickelhaupt Arboretum (14 acres) is a non-profit arboretum located in Clinton, Iowa. It is open dawn to dusk daily without charge. The arboretum was established by Bob and Frances Bickelhaupt around their home and given to the public in 1970. The B ...

, US. Acc. no. 02–018 *

Brenton Arboretum The Brenton Arboretum is a 141-acre arboretum and public garden in Dallas Center, Iowa, United States, established in 1997. The arboretum displays 175 native Iowa trees and shrubs suitable to the site, as well as many other tree species which can ...

, US. 5 trees, acquired 2009. Acc. no. not known. * Chicago Botanic Garden, US. 1 tree, planted in the Parking Lots; no other details available. *

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&nbs ...

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US. 2 trees, no acc. details available. * Holden Arboretum, US. Acc. no. 00–124 * Morton Arboretum, US. Acc. nos. 274–97, 109–2006. *

Smith College Smith College is a Private university, private Liberal arts colleges in the United States, liberal arts Women's colleges in the United States, women's college in Northampton, Massachusetts. It was chartered in 1871 by Sophia Smith (Smith College ...

, US. Acc. no. 36405 * University of Idaho Arboretum, US. Two trees. Acc. no. 2000089 ;Europe * Grange Farm Arboretum, Lincolnshire, UK. Acc. no. 1141.

References

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