Ulmus americana 'Delaware'

Elm cultivar

Ulmus americana 'Delaware'
Delaware Elm, USDA Washington
Species	Ulmus americana
Cultivar	'Delaware'
Origin	USDA, Morristown, New Jersey, US

The American Elm cultivar 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 trials at Morristown, New Jersey.^[1]

Description

The tree has a relatively low stature and "undesirable" branching habit.^[1]^[2]

Pests and diseases

Further disease-resistance trials were conducted by both the USDA and the United States National Arboretum 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.

Cultivation

The original tree, which had been moved to the USDA National Arboretum, Washington, D. C. in 1948, died from unknown causes (probably elm yellows, by some accounts) in 1980, but a clone survives at the Denver Botanic Gardens, as 'Delaware II'. Seven specimens stand in the National Mall area, Washington D.C.^[3]^[4] ^[5] 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 or Australasia.

'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, US (2011)

Synonymy

'Delaware II'.

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

Accessions

Wikispecies has information related to Ulmus americana 'Delaware'.

North America

Brooklyn Botanic Garden, [1] Archived 2016-02-01 at the Wayback Machine, New York, US. Acc. no. 980489.
Dawes Arboretum, US. [2], Newark, Ohio, US. 1 tree, listed as 'Delaware #2'; no acc. details available.
Denver Botanic Gardens, US. No details available.
Dominion Arboretum, Canada. [3]. No details available.

References

^ ^a ^b Santamour, Frank S.; Bentz, Susan E. (May 1995). "Updated Checklist of Elm (Ulmus) Cultivars for use in North America". Journal of Arboriculture. 21 (3): 122–131. Retrieved 20 June 2016.
^ 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.
^ 'Delaware', Smithsonian Gardens, si.gardenexplorer.org
^ 'Delaware' before pruning, National Museum of Natural History, Constitution Avenue NW, Washington DC - Google Maps, March 2011, access date: 18 October 2022
^ Pruned 'Delaware', National Museum of Natural History, Constitution Avenue NW, Washington DC - Google Maps, August 2022, access date: 17 October 2022

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