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

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 ...

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 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 ...

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, 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, Professor of Horticulture at the

University of Georgia , mottoeng = "To teach, to serve, and to inquire into the nature of things.""To serve" was later added to the motto without changing the seal; the Latin motto directly translates as "To teach and to inquire into the nature of things." , establ ...

br>
on account of its 'wild' growth and splaying branches.

Pests and diseases

Although resistant 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 the United States, the tree is moderately susceptible to insects, notably 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 ...

'',McPherson, G. et al. (2008). National elm trial: Initial report from Northern California. ''Western Arborist'', Fall 2009, 32–36.

Japanese beetle The Japanese beetle (''Popillia japonica'') is a species of scarab beetle. The adult measures in length and in width, has iridescent copper-colored elytra and a green thorax and head. It is not very destructive in Japan (where it is control ...

Brady, 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 ''Lymantria dispar'', also known as the gypsy moth or the spongy moth, is a species of moth in the family Erebidae. ''Lymantria dispar'' is subdivided into several subspecies, with subspecies such as ''L. d. dispar'' and ''L. d. japonica'' bei ...

Cultivation

is vigorous and robust, adjudged the third fastest-growing cultivar of 17 assessed by the

University of Minnesota The University of Minnesota, formally the University of Minnesota, Twin Cities, (UMN Twin Cities, the U of M, or Minnesota) is a public land-grant research university in the Twin Cities of Minneapolis and Saint Paul, Minnesota, United States. ...

and fourth out of 15 in trials at

U C Davis The University of California, Davis (UC Davis, UCD, or Davis) is a public land-grant research university near Davis, California. Named a Public Ivy, it is the northernmost of the ten campuses of the University of California system. The instit ...

. 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, Japan. the tree was found cold-hardy to −40° C. was introduced by Chicagoland Grows and is currently being evaluated in the National Elm TrialCSU Shade Tree Lab
coordinated by Colorado State University. 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, US. Acc. no. 131–2002 * Bickelhaupt Arboretum, 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 ca ...

, US. 5 trees, acquired 2009. Acc. no. not known. *

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 Shor ...

, US. 1 tree, planted in the Parking Lots; no other details available. * Dawes Arboretumbr>
US. 2 trees, no acc. details available. *

Holden Arboretum The Holden Arboretum, in Kirtland, Ohio, is one of the largest arboreta and botanical gardens in the United States, with more than , including devoted to collections and gardens. Diverse natural areas and ecologically sensitive habitats make up t ...

, US. Acc. no. 00–124 *

, US. Acc. nos. 274–97, 109–2006. * Smith College, US. Acc. no. 36405 *

University of Idaho The University of Idaho (U of I, or UIdaho) is a public land-grant research university in Moscow, Idaho. It is the state's land-grant and primary research university,, and the lead university in the Idaho Space Grant Consortium. The Universit ...

Arboretum, US. Two trees. Acc. no. 2000089 ;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) ...

Lincolnshire Lincolnshire (abbreviated Lincs.) is a Counties of England, 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-we ...

, UK. Acc. no. 1141.

References

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