Ulmus 'Morton Stalwart'

Elm cultivar

Ulmus 'Morton Stalwart'
Commendation, 14 years old.^[1]
Genus	Ulmus
Hybrid parentage	Accolade × (U. minor × U. pumila)
Cultivar	'Morton Stalwart' = Commendation
Origin	US

Ulmus 'Morton Stalwart' (selling name Commendation), is a Morton Arboretum hybrid cultivar arising from a controlled crossing of Accolade with the hybrid of a Field Elm U. minor from eastern Russia and a Siberian Elm U. pumila.^[2]^[3] Tested in the US National Elm Trial coordinated by Colorado State University,^[4] Commendation averaged a survival rate of 85% after 10 years.^[5]

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 Triumph and Vanguard, as 'ugly' by Michael Dirr, Professor of Horticulture at the University of Georgia [1], 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,^[3] notably elm leaf beetle Xanthogaleruca luteola,^[6] Japanese beetle^[7] and Gypsy moth.

Cultivation

Commendation 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.^[6] The tree is also extremely tolerant of drought^[8] and cold; in artificial freezing tests at the Morton Arboretum^[9] the tree was found cold-hardy to −40°C.

Commendation was introduced by Chicagoland Grows^[10]^[3] and is currently being evaluated in the National Elm Trial^[11] 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.

Ulmus 'Morton Stalwart' Commendation™, Esplanade, North Lake, Chicago Botanic Garden (September 2019)
Boles of 'Morton Stalwart' Commendation™

Accessions

North America

Arnold Arboretum, US. Acc. no. 131–2002
Bickelhaupt Arboretum, US. Acc. no. 02–018
Brenton Arboretum, 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 [2], 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, US. Acc. no. 36405
University of Idaho Arboretum, US. Two trees. Acc. no. 2000089

Europe

Grange Farm Arboretum, Lincolnshire, UK. Acc. no. 1141.

References

^ Cirrus Digital Commendation Elm
^ Cirrus Digital Hybrid Elm - Ulmus (carpinifolia x pumila)
^ ^a ^b ^c Morton Arboretum Commendation Elm
^ "AgSci-Home page". Archived from the original on 2008-02-26.
^ Griffin, J.; et al. (2017). "Ten-Year Performance of the United States National Elm Trial" (PDF). Arboriculture & Urban Forestry. 43(3):107–120. International Society of Arboriculture, Atlanta, US.
^ ^a ^b McPherson, G. et al. (2008). National elm trial: Initial report from Northern California. Western Arborist, Fall 2009, 32–36.
^ 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.
^ Giblin, C. P. & Gillman, J. H. (2006). Elms for the Twin Cities: A Guide for Selection and Maintenance. University of Minnesota.
^ Shirazi, 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.
^ "Chicagoland Grows® Plant Introduction Program".
^ CSU Shade Tree Lab Archived 2008-02-26 at the Wayback Machine

Elm species, varieties, hybrids, hybrid cultivars and species cultivars

Species, varieties and subspecies

U. alata (Winged elm)
U. americana (American elm)
U. americana var. floridana (Florida elm)
U. bergmanniana (Bergmann's elm)
U. bergmanniana var. bergmanniana
U. bergmanniana var. lasiophylla
U. castaneifolia (Chestnut-leafed or multinerved elm)
U. changii (Hangzhou elm)
U. changii var. changii
U. changii var. kunmingensis (Kunming elm)
U. chenmoui (Chenmou or Langya Mountain elm)
U. chumlia
U. crassifolia (Cedar or Texas cedar elm)
U. davidiana (David or Father David elm)
U. davidiana var. davidiana
U. davidiana var. japonica (Japanese elm)
U. elongata (Long raceme elm)
U. gaussenii (Anhui or hairy elm)
U. glabra (Wych or scots elm)
U. glaucescens (Gansu elm)
U. glaucescens var. glaucescens
U. glaucescens var. lasiocarpa (hairy-fruited glaucescent elm)
U. harbinensis (Harbin elm)
U. ismaelis
U. laciniata (Manchurian cut-leaf or lobed elm)
U. laciniata var. nikkoensis (Nikko elm)
U. laevis (European white elm)
U. laevis var. celtidea
U. laevis var. parvifolia
U. laevis var. simplicidens
U. lamellosa (Hebei elm)
U. lanceifolia (Vietnam elm)
U. macrocarpa (Large-fruited elm)
U. macrocarpa var. glabra
U. macrocarpa var. macrocarpa
U. mexicana (Mexican elm)
U. microcarpa (Tibetan elm)
U. minor (Field elm)
U. minor subsp. minor
U. minor var. italica
U. parvifolia (Chinese or lacebark elm)
U. parvifolia var. coreana (Korean elm)
U. prunifolia (Cherry-leafed elm)
U. pseudopropinqua (Harbin spring elm)
U. pumila (Siberian elm)
U. rubra (Slippery elm)
U. serotina (September elm)
U. szechuanica (Szechuan (Sichuan) or red-fruited elm)
U. thomasii (Rock or cork elm)
U. uyematsui (Alishan elm)
U. villosa (Cherry-bark or marn elm)
U. wallichiana (Himalayan or kashmir elm)
U. wallichiana subsp. wallichiana
U. wallichiana subsp. xanthoderma
U. wallichiana var. tomentosa

Disputed species, varieties and subspecies

U. boissieri
U. minor subsp. canescens (Grey, grey-leafed or hoary elm)
U. elliptica

Hybrids

U. davidiana var. japonica × U. minor
U. × arbuscula
U. × arkansana
U. × brandisiana
U. × diversifolia
U. × hollandica (Dutch elm)
U. × hollandica var. insularum
U. × intermedia
U. × mesocarpa

Species cultivars

American elm	American Liberty Ascendens Augustine Aurea Beaverlodge Beebe's Weeping Brandon Burgoyne JFS Prince II College Columnaris Creole Queen Deadfree Delaware Exhibition Fiorei Flick's Spreader Folia Aurea Variegata Great Plains Hines Incisa Independence Iowa State Jackson Jefferson Kimley Klehmii L'Assomption Lake City Lewis & Clark Littleford Maine Markham Miller Park Minneapolis Park Moline Morden New Harmony Nigricans Patmore Pendula Penn Treaty Princeton Pyramidata Queen City Sheyenne Skinner Upright St. Croix Star Valley Forge Variegata Vase Washington
Cedar elm	Brazos Rim
Chinese elm	A-1 A. Ross Central Park Blizzard BSNUPF Burgundy Burnley Select Catlin Chessins Churchyard Cork Bark D. B. Cole Drake Dynasty Ed Wood Elsmo Emer I Emer II Emerald Prairie Frosty Garden City Clone Geisha Glory Golden Rey Hallelujah Hokkaido Jade Empress King's Choice Littleleaf Lois Hole Matthew Milliken Nire-keyaki Ohio Orange Ribbon Pathfinder Pendens Prairie Shade Prince Richard Red Fall Sabamiki Sagei Seiju Select 380 Sempervirens Small Frye State Fair Stone's Dwarf Taiwan The Thinker Todd True Green UPMTF Ware's Yarralumla Yatsubusa Zettler Ulmus parvifolia f. lanceolata
European white elm	Aureovariegata Colorans Helena Ornata Pendula Punctata Urticifolia
Field elm	Ademuz Albo-Dentata Amplifolia Argenteo-Variegata Atinia Atinia Pyramidalis Atinia Variegata Bea Schwarz Biltii Christine Buisman Concavaefolia Coritana Cretensis Cucullata Cucullata Variegata Dehesa de Amaniel Dehesa de la Villa Dicksonii Dijkwel Erecta Folia Alba-Punctata Glandulosa Goodyeri Hoersholmiensis Holmstruph Hunnybunii Hunnybunii pseudo-Stricta Laciniata Lanuginosa Majadahonda Microphylla Pendula Microphylla Purpurea Microphylla Rubra Monumentalis Pendula Picturata Plotii Propendens Punctata Purpurascens Purpurea Retiro Reverti Rugosa Rueppellii Sarniensis Schuurhoek Silvery Gem Sowerbyi Stricta Suberosa Umbraculifera Gracilis Umbraculifera Viminalis Viminalis Aurea Viminalis Betulaefolia Viminalis Gracilis Viminalis Incisa Viminalis Marginata Viminalis Pendula Viminalis Pulverulenta Viminalis Stricta Virgata Webbiana
Japanese elm	Discovery Freedom Jacan JFS-Bieberich Mitsui Centennial Prospector Reperta Reseda Thomson Validation
Siberian elm	Ansaloni Aurea Aurescens Chinkota Dropmore Dwarf Weeper Green King Hansen Harbin Manchu Mauro Mr. Buzz Park Royal Pendula Pinnato-ramosa Poort Bulten Puszta Pyramidalis Fiorei Zhonghua Jinye
Winged elm	Lace Parasol
Wych elm	Albo-Variegata Australis Camperdownii Cebennensis Concavaefolia Cornuta Corylifolia Purpurea Corylifolia Dovaei Fastigiata Macrophylla Fastigiata Stricta Fastigiata Variegata Firma Flava Gigantea Gittisham Grandidentata Holgeri Horizontalis Insularis Latifolia Latifolia Aurea Latifolia Aureo-Variegata Latifolia Nigricans Luteo Variegata Lutescens Macrophylla Maculata Minor Nana Nigra Nitida Oblongata Pendula Macrophylla Pendula Variegata Pyrenaica Spectabilis Superba Tomentosa

Hybrid cultivars

Androssowii Amsterdam Arno Cathedral Clusius Columella Den Haag Dodoens Escaillard Fiorente Frontier Fuente Umbria Homestead Karagatch Lobel Morfeo Morton Morton Glossy Morton Plainsman Morton Red Tip Morton Stalwart Nanguen New Horizon Patriot Plantyn Plinio Rebella Rebona Recerta Regal Repura Revera San Zanobi Sapporo Autumn Gold Sapporo Gold 2 Stavast Toledo Urban Wanoux Wingham
Dutch elm	Alba Angustifolia Balder Belgica Blandford Canadian Giant Cicestria Cinerea Commelin Dampieri Dauvessei Daveyi Dumont Elegantissima Eleganto-Variegata Etrusca Fastigiata Fjerrestad Folia Rhomboidea Freja Fulva Gaujardii Groeneveld Haarlemensis Klemmer Loke Macrophylla Aurea Major Microphylla Modiolina Muscaviensis Odin Pioneer Pitteurs Serpentina Smithii Superba Tricolor Tyr Vegeta Viminalis Viscosa Wentworthii Pendula Wredei Ypreau
U. × intermedia	Coolshade Fremont Improved Coolshade Lincoln Rosehill Willis