Ulmus × hollandica 'Klemmer', or Flanders Elm, is probably one of a number of hybrids arising from the crossing of Wych Elm (Ulmus glabra) with a variety of Field Elm (Ulmus minor), making it a variety of Ulmus × hollandica. Originating in the Bruges area, it was described by Gillekens in 1891 as l'orme champêtre des Flandres in a paper which noted its local name, klemmer, and its rapid growth in an 1878–91 trial.Gillekens, Léopold Guillaume, Éléments d'arboriculture forestière (1891), p.40 Kew,Photograph of 'Klemmer' leaves in Kew in Gerald Wilkinson, Epitaph for the Elm, Hutchinson, London 1978 ( / 0-09-921280-3) Henry (1913), and Krüssmann (1976)Krüssmann, Johann Gerd, Handbuch der Laubgehölze (Vol. 3) (Paul Parey, Berlin and Hamburg, 1976); trans. Michael E. Epp, Manual of Cultivated Broad-Leaved Trees and Shrubs (Vol. 3) (Batsford, Timber Press, Beaverton, Oregon, 1984-6), p.410 listed it as an Ulmus × hollandica cultivar, though Henry noted its "similarity in some respects" to field elm Ulmus minor, while Green went as far as to regard it as "possibly U. carpinifolia" (:minor).

Etymology The name 'Klemmer' derives from the Flemish for 'climber', a reference to the tree's rapid growth and lofty height. Klemmeri, used by the Späth nursery among others, is a misnomer, incorrectly implying a proper noun Klemmer.

Not to be confused with 'Klehmii', a cultivar of Ulmus americana named for Charles Klehm, an Illinois nurseryman.

Description 'Klemmer' is a tall, fast growing tree, with a straight cylindrical stem and ascending branches, initially forming a narrow, conical or pyramidal head which later broadens, and producing numerous root-suckers and some epicormic shoots.Photo of Morton Arboretum 'Klemmer' (centre of picture) The bark, smooth in young trees, is later fissured, forming irregular 'scales' in mature specimens.Photographs of Ulmus × hollandica 'Klemmer' (trees, bark, leaves, shoots), Morton Arboretum, 'Ulmus Series', acorn.mortonarb.org The leaves, their upper surface middle green, are ovate, up to 7.5 cm (3 in) long (Krüssmann says up to 10 cm) and up to 5.0 cm (2 in) broad, shortly acuminate at the apex, scabrous and glabrescent, the margins slightly crispate."Herbarium specimen BR0000026204994V". Botanic Garden, Meise. Sheet labelled Klemmer rouge, Ypres area (C. Aigret; 1905); Short-shoot leaves; sheet described as U. × hollandica Mill. 'Klemmeri' Rehder, Arnold Arboretum, 1930 (sheet made by Christine Buisman during her study-year at Radcliffe College, Boston, Massachusetts, from material harvested at Arnold Arboretum); Sheet described as U. × hollandica Mill. 'Klemmeri', Wageningen Arboretum, 1962; Long shoot. Sheet described as U. × hollandica Mill. 'Klemmeri' (from Späth)cirrusimage.com Ulmus 'Klemmer' at Morton Arboretum (F. J. Fontaine likened the leaves to "the fairly narrow light green leaves of 'Superba', but with a somewhat rougher upper surface".) The petiole is 1 to 1.5 cm long in canopy leaves.Naturalis Biodiversity Center; specimen WAG.1847085, U. × hollandica Mill. 'Klemmeri', Wageningen Arboretum, 1962 The seed is situated close to the notch of the samara. Fruit; sheet described as U. × hollandica Mill. 'Klemmeri' Rehder, Arnold Arboretum, 1930 (sheet made by Christine Buisman during her study-year at Radcliffe College, Boston, Massachusetts, from material harvested at Arnold Arboretum) The timber is reddish in hue, strong but liable to warping. Feneau noted (1902) that young trees were susceptible to frost damage.

Pests and diseases 'Klemmer' has no significant resistance to Dutch elm disease.

Cultivation

Common in western Flanders by the 1880s, before World War I and the first Dutch elm disease epidemic, 'Klemmer' was widely supplied and planted in avenues across Belgium and in the Département du Nord, France, where it was much esteemed for its timber and rapid growth, and where it was considered suitable for street planting because of its narrow form. Nanot (1885) and Aigret (1905) reported it as planted in the environs of Paris. F. J. Fontaine noted in 1968 that 'Klemmer', owing to Dutch elm disease, "occurs rarely or no longer in nurseries in Belgium, but is still used in northern France alongside the 'Dumont' elm, though to a lesser extent". Ulmus hollandica klemmeri was present in The Hague and Utrecht in the 1930s.Christine Buisman, 'Verslag van de onderzoekingen over de iepenziekte, verricht in het phytopathologisch laboratorium Willie Commelin scholten te Baarn, gedurende 1932 (1)', Tijdschrift over Planteziekte, Vol 39 Iss 4, April  1933, pp.86-87

The tree was introduced to the USA c.1871, appearing as U. campestris Clemmerii, "a tree of fine form, much used in Belgium for planting along avenues", in the catalogues of the Mount Hope Nursery (also known as Ellwanger and Barry) of Rochester, New York.'Descriptive Catalogue of Ornamental Trees & Shrubs', no.2, Mount Hope Nursery, Rochester, 1871; p.6 The Späth nursery of Berlin supplied an U. campestris Clemmeri to the Dominion Arboretum, Ottawa, Canada, in 1893. By his 1903 catalogue Späth had renamed the cultivar U. Klemmeri, suggesting doubts about its botanical status.

Kew had two specimens, obtained in 1908 from the French nursery, Barbier Frères; one was still present in the late 1970s. S. G. A. Doorenbos, Director of The Hague Parks Department from 1927, introduced 'Klemmer', sourced from Kew, to Belmonte Arboretum, Wageningen in the early 1930s.Naturalis Biodiversity Center, specimen WAG.1847080: U. × hollandica Mill. var. 'Klemmer', Wageningen Arboretum, 1932 Apart from the Wakehurst Place hedging specimen (see 'Notable trees'), no 'Klemmer' are known to survive in the UK. In 2025 Brighton and Hove Council listed by this name, without provenance or identification information,'Rare elms in the spotlight for Sussex Tree Festival', 11 June 2025 an elm in Royal Pavilion Gardens lacking the distinctive straight stem and narrow profile of 'Klemmer'. Elm in Royal Pavilion Gardens, alongside Pavilion Parade, Brighton - Google Maps, April 2021, access date: 26 June 2025

Notable trees One of two specimens obtained in 1908 from the Barbier Nursery, France, by the Royal Botanic Gardens Kew survives at Wakehurst Place, maintained as a hedging plant, too low to attract the attention of Scolytus beetles.Webber, J. F. (2000). 'Insect Vector Behavior & The Evolution of Dutch Elm Disease'. in: Dunn, C. P. (ed.) The Elms - Breeding, Conservation & Disease Management. Springer Nature. In the US, three 'Klemmer' elms, sourced from Arnold Arboretum, survive (2018) at the Morton Arboretum, Illinois.

The Ladywell Fields elm A large European White Elm Ulmus laevis (identity confirmed by dendrologist Owen Johnson from its distinctive fruitJohnson, O. (2011). Champion Trees of Britain & Ireland, Kew Publishing, Kew, London. .) growing in the Ladywell Fields public park in Lewisham, London, was misidentified in 1997 as a 'Klemmer' Dutch elm. An information board, erected in front of the tree by Lewisham Council, bears (2025) the erroneous name and depicts another tree (one of the Morton Arboretum 'Klemmer'), but correctly shows the specimen's pedunculate White Elm fruit, differing from the sessile fruit of Dutch elm.The Lewisham Elm: Article on www.treesforcities.org , www.waymarking.com

Synonymy l'orme champêtre klemmer: Gillekens, Éléments d'arboriculture forestière 41, 1891 'Klemmer Rouge': Feneau.Bulletin de la Société centrale forestière de Belgique, 9: 162, 1902"Herbarium specimen BR0000026204994V", Botanic Garden Meise|Botanic Garden, Meise; Klemmer rouge, Ypres area; C. Aigret; 1905 Ulmus campestris (: minor) var. Clemmeri: Lavallée Arboretum Segrezianum. 235, 1877. Ulmus klemeri: Späth nursery, Berlin, 1900.

Accessions

North America Morton Arboretum, US. Acc. no. 535–49 3 trees, sourced from Arnold Arboretum.

Europe Wakehurst Place Garden Wakehurst Place, UK. Acc. no. 1908–14108

References

External links Ulmus 'Klemmer', Michigan State University Plant Encyclopedia.