Ulmus glabra 'Nana'

The dwarf wych elm cultivar Ulmus glabra 'Nana', a very slow growing shrub that with time forms a small tree, is of unknown origin. It was listed in the Simon-Louis (Metz, France) 1869 catalogue as Ulmus montana nana.^[1][2] Henry (1913), referring his readers to an account of the Kew specimen in the journal Woods and Forests, 1884,^[3] suggested that it may have originated from a witch's broom. It is usually classified as a form of Ulmus glabra and is known widely as the 'Dwarf Wych Elm'. However, the ancestry of 'Nana' has been disputed in more recent years, Melville considering the specimen once grown at Kew to have been a cultivar of Ulmus × hollandica.^[4]

Ulmus glabra 'Nana'
'Nana', Royal Botanic Gardens Edinburgh (1989)
Species	Ulmus glabra
Cultivar	'Nana'
Origin	Europe

Not to be confused with Loudon's U. campestris nana (1838), a dwarf field elm "with small, narrow, rough leaves",^[5] or with Ulmus 'Monstrosa', a long-petioled dwarf field-elm cultivar sometimes referred to as 'Nana Monstrosa'.^[6][7]

Description

The tree rarely exceeds 5 m in height, but is often broader.^[8] The dark green leaves are smaller than the wych type, 5–9 centimeters (2.0–3.5 in) long, often with one or two cusp-like lobes either side of the apex.^[7] The thick twigs, short petiole and diminutive samara with seed close to base, all point to U. glabra origin. A specimen at Kew was described by Henry as 'a slow-growing hemispherical bush that has not increased appreciably in size for many years'.^[2] Green describes 'Nana' as growing some 60 centimeters (24 in) in 10 to 12 years.^[9]

• 
  'Nana' in winter, Royal Botanic Gardens, Kew (2012)
• 
  'Nana' in late summer, Royal Botanic Gardens Edinburgh (2016)
• 
  Bole of same
• 
  Samarae
• 
  'Nana' leaves, spring
• 
  'Nana' leaves, summer

Pests and diseases

The low height of the tree should ensure that it avoids colonization by Scolytus bark beetles and thus remain free of Dutch elm disease. It has been noted that shrub-elms are usually less prone to infection.^[10]

Cultivation

The Späth nursery of Berlin marketed U. montana nana in the late 19th century.^[11] It was introduced to the Dominion Arboretum, Ottawa, Canada, in 1898.^[12] Ulmus montana nana, 'Dwarf Scotch Elm', was introduced to the USA in the late 19th century, appearing as a "new variety" in the 1897 catalogue of the Mount Hope Nursery (also known as Ellwanger and Barry) of Rochester, New York.^[13] A 'Nana' appeared as U. nana, 'Dwarf American elm', a "very small" elm with compact habit, in Kelsey's 1904 catalogue, New York.^[14] (Other European elms described as 'American' by various nurseries include 'Vegeta',^[15] 'Scampstoniensis',^[16][17] and 'Lutescens'.^[2]) There was a well-grown specimen in Missouri Botanical Garden in the mid 20th century.^[18] The tree is still occasionally found in arboreta and gardens in the UK, Europe and North America. It is not known in Australasia. 'Nana' remains in cultivation in Europe (see Nurseries).

A shrub elm sold in the Netherlands as U. 'Monstrosa' appeared from its leaf and short petiole to be 'Nana',^[19] while one cultivated in the Royal Botanic Garden Edinburgh in the early 20th century as 'Nana' appears from its leaf and long petiole to have been 'Monstrosa'.^[20] The current RBGE 'Nana' is the authentic wych clone (2017).

• 
  Pruned 'Nana', Sir Harold Hillier Gardens, UK (2008)
• 
  Young 'Nana'
• 
  'Nana' in flower, RBGE

Notable trees

The specimen of 'Nana' in the University Parks (North Walk), Oxford, UK, has attained a height of about 6 m (2017).^[21] Another grew in Alexandra Park, East Sussex, UK, measured 6 m high, 38 cm dia. at 1 m from ground in 1980 but is possibly now lost.^[22]

• 
  'Nana' in Oxford University Parks (2017)

Synonymy

• Ulmus scabra nana Dipp.^[23]
• Ulmus glabra 'Bush': Plant Buyer's Guide, ed. 5, 253, 1949, without description.

Accessions

North America

• Arnold Arboretum, UK. Acc. no. 448–88

Europe

• Royal Botanic Garden Edinburgh, UK. Acc. no. 19021001, two trees in excellent condition (2004).
• Royal Horticultural Society Gardens Wisley, UK. Two specimens, no details available.
• Sir Harold Hillier Gardens, Romsey, Hampshire, UK. Acc. nos. 1978.1680, 1978.4729
• University of Copenhagen Botanic Gardens, Denmark. No details available.
• Grange Farm Arboretum, Lincolnshire, UK. Acc. no. 1128. Accessioned as U. 'Monstrosa'.

Nurseries

North America

None known

Europe

• A Touch of Green , Amstelveen, Netherlands.
• Arboretum Waasland , Nieuwkerken-Waas, Belgium.
• H. Kolster , Boskoop, Netherlands.
• PlantenTuin Esveld , Netherlands.
• Szkółki Konieczko , Gogolin, Poland.

References

1. Simon-Louis Catalogue, p. 97, 1869
2. Elwes, Henry John; Henry, Augustine (1913). The Trees of Great Britain & Ireland. Vol. 7. p. 1868.
3. Woods and Forests, 1884, p.482
4. Melville, R. (1978). On the discrimination of species in hybrid swarms with special reference to Ulmus and the nomenclature of U. minor (Mill.) and U. carpinifolia (Gled.). Taxon 27: 345-351.
5. Loudon, John Claudius (1838). Arboretum et fruticetum Britannicum. Vol. 3. p. 1404., p.1378
6. Rehder, Alfred. "Ulmaceae". Bibliography of cultivated trees and shrubs hardy in the cooler temperate regions of the Northern Hemisphere. Jamaica Plain, Massachusetts: The Arnold Arboretum of Harvard University. pp. 135–143. Retrieved 18 October 2017.
7. Krüssman, Gerd, Manual of Cultivated Broad-Leaved Trees & Shrubs (1984 vol. 3)
8. White, J. & More, D. (2003) Trees of Britain & Northern Europe. Cassell's, London.
9. Green, Peter Shaw (1964). "Registration of cultivar names in Ulmus". Arnoldia. 24 (6–8). Arnold Arboretum, Harvard University: 41–80. Retrieved 16 February 2017.
10. Rafaël Govaerts, Kris Michielsen and Eike Jablonski, 'Untraced weeping broadleaf cultivars: an overview', dendrology.lu
11. Katalog (PDF). Vol. 108. Berlin, Germany: L. Späth Baumschulenweg. 1902–1903. pp. 132–133.
12. Saunders, William; Macoun, William Tyrrell (1899). Catalogue of the trees and shrubs in the arboretum and botanic gardens at the central experimental farm (2 ed.). pp. 74–75.
13. Ellwanger & Barry, Mount Hope Nurseries, Rochester, 1897 catalogue; p.9
14. General catalogue, 1904 : choice hardy trees, shrubs, evergreens, roses, herbaceous plants, fruits, etc. New York: Frederick W. Kelsey. 1904. p. 18.
15. Arboretum et Fruticetum Britannicum, 3: 1398, 1404
16. Winchelsea, C.C. (1910). "Weeping trees". The Gardeners' Magazine. 53: 501.
17. Anthony waterer's catalogue. 1880. p. 20.
18. 'Nana' in Missouri Botanical Garden; Beilmann. A. P., 'Some Ornamental Elms', Missouri Botanical Garden Bulletin, Vol.32, No.4, April 1944; p.74
19. Photographs of plant sold as 'Monstrosa' in Holland: Herman Geers Dwarf & Miniature Plants,
20. barcodes E00824863 & E00212441
21. parks.ox.ac.uk/tree/alpha.htm
22. Johnson, Owen (ed.) (2003). Champion Trees of Britain & Ireland. Whittet Press, ISBN 978-1-873580-61-5.
23. Späth, Ludwig (1930). Späth-Buch, 1720-1930. Berlin: Self published. pp. 311–313, 351–352.