Ulmus pumila, the Siberian elm, is a tree native to Asia. It is also known as the Asiatic elm and dwarf elm, but sometimes miscalled the 'Chinese Elm'. U. pumila has been widely cultivated throughout Asia, North America, Argentina, and southern Europe, becoming naturalized in many places, notably across much of the United States.
Ulmus wallichianaPlanch., the Himalayan elm, also known as the Kashmir elm and Bhutan elm, is a mountain tree ranging from central Nuristan in Afghanistan, through northern Pakistan and northern India to western Nepal at elevations of 800–3000 m. Although dissimilar in appearance, its common name is occasionally used in error for the cherry bark elm Ulmus villosa, which is also endemic to the Kashmir, but inhabits the valleys, not the mountain slopes. The species is closely related to the wych elm U. glabra.
Ulmus davidiana var. japonica, the Japanese elm, is one of the larger and more graceful Asiatic elms, endemic to much of continental northeast Asia and Japan, where it grows in swamp forest on young alluvial soils, although much of this habitat has now been lost to intensive rice cultivation.
Ulmus × hollandica 'Vegeta', sometimes known as the Huntingdon Elm, is an old English hybrid cultivar raised at Brampton, near Huntingdon, by nurserymen Wood & Ingram in 1746, allegedly from seed collected at nearby Hinchingbrooke Park. In Augustine Henry's day, in the later 19th century, the elms in Hinchingbrooke Park were U. nitens. Richens, noting that wych elm is rare in Huntingdonshire, normally flowering four to six weeks later than field elm, pointed out that unusually favourable circumstances would have had to coincide to produce such seed: "It is possible that, some time in the eighteenth century, the threefold requirements of synchronous flowering of the two species, a south-west wind", "and a mild spring permitting the ripening of the samaras, were met."
Ulmus laciniata(Trautv.) Mayr, known variously as the Manchurian, cut-leaf, or lobed elm, is a deciduous tree native to the humid ravine forests of Japan, Korea, northern China, eastern Siberia and Sakhalin, growing alongside Cercidiphyllum japonicum, Aesculus turbinata, and Pterocarya rhoifolia, at elevations of 700–2200 m, though sometimes lower in more northern latitudes, notably in Hokkaido.
Ulmus chenmouiW. C. Cheng, commonly known as the Chenmou, or Langya Mountain elm, is a small deciduous tree from the more temperate provinces of Anhui and Jiangsu in eastern China, where it is found at elevations below 200 m on the Langya Shan and Baohua Shan mountains. The tree was unknown in the West until 1979, when seeds were sent from Beijing to the De Dorschkamp research institute at Wageningen in the Netherlands.
Ulmus × hollandica 'Commelin' is a Dutch hybrid cultivar released for sale in 1960. The tree was raised at Baarn as clone 274 by the Foundation Willie Commelin Scholten Phytopathological Laboratory in 1940, from a crossing of Ulmus × hollandica 'Vegeta' and clone 1, an Ulmus minor selected from a 1929 elm seedlings lot obtained from the Barbier nursery, Orléans.
The Dutch hybrid cultivar Ulmus 'Dodoens' was derived from a selfed seedling of a crossing of the Exeter Elm Ulmus 'Exoniensis' with the Himalayan Elm Ulmus wallichiana at the Dorschkamp Research Institute for Forestry & Landscape Planning, Wageningen. The tree was one of several cultivars prepared for release in 1970, but delayed by the outbreak of the second, far more aggressive strain of Dutch elm disease.
The Dutch hybrid elm cultivar Ulmus × hollandica 'Groeneveld' was cloned in 1949 at the De Dorschkamp Institute, Wageningen, and released in 1963 in response to the earlier, less virulent form of Dutch elm disease that afflicted Europe shortly after the First World War. The cultivar was derived from a crossing of Dutch clones '49', and '1', a Field Elm Ulmus minor found in central France and marketed by the Barbier nursery in Orléans.
Ulmus 'Homestead' is an American hybrid elm cultivar raised by Alden Townsend of the United States National Arboretum at the Nursery Crops Laboratory in Delaware, Ohio. The cultivar arose from a 1970 crossing of the Siberian Elm Ulmus pumila with the hybrid N 215, the latter grown from seed sent in 1960 to the University of Wisconsin-Madison elm breeding team by Hans Heybroek of the De Dorschkamp Research Institute in the Netherlands. Tested in the US National Elm Trial coordinated by Colorado State University, 'Homestead' averaged a survival rate of 85% after 10 years. 'Homestead' was released to commerce without patent restrictions in 1984.
Ulmus 'Plantyn' was one of three Dutch hybrid elms released by the Dorschkamp Research Institute for Forestry & Landscape Planning, Wageningen, in 1973. Derived from a crossing of the Dutch hybrids '202' and '302', it was to prove of great significance in later developments. A selfed seedling was to become the first Dutch clone to prove effectively immune to disease, released in 1989 as 'Columella'. 'Plantyn' was also destined to be the female parent of Lutèce released in 2002. In Italy, 'Plantyn' was used again as female parent in hybridizations with the Siberian Elm Ulmus pumila by the Istituto per la Protezione delle Piante (IPP), to create three new cultivars better adapted to the Mediterranean climate.
The hybrid elm cultivar Ulmus × hollandica 'Belgica', one of a number of hybrids arising from the crossing of Wych Elm with a variety of Field Elm, was reputedly raised in the nurseries of the Abbey of the Dunes, Veurne, in 1694. Popular throughout Belgium and the Netherlands in the 19th century both as an ornamental and as a shelter-belt tree, it was the 'Hollandse iep' in these countries, as distinct from the tree known as 'Dutch Elm' in Great Britain and Ireland since the 17th century: Ulmus × hollandica 'Major'. In Francophone Belgium it was known as orme gras de Malines.
The Field Elm cultivar Ulmus minor 'Hoersholmiensis', Hoersholm elm, originated from seed sown at the Hørsholm Planteskole, Denmark, c. 1885, where it was propagated by the nursery proprietor Lars Nielsen. The Späth nursery of Berlin, however, which marketed 'Hoersholmiensis' in the interwar period, considered it a hybrid rather than a form of field elm, a view shared by Christine Buisman, who in 1931 labelled a herbarium specimen from a Späth-sourced tree in The Hague as a form of Ulmus × hollandica.
Ulmus 'Exoniensis', the Exeter elm, was discovered near Exeter, England, in 1826, and propagated by the Ford & Please nursery in that city. Traditionally believed to be a cultivar of the Wych Elm U. glabra, its fastigiate shape when young, upward-curving tracery, small samarae and leaves, late leaf-flush and late leaf-fall, taken with its south-west England provenance, suggest a link with the Cornish Elm, which shares these characteristics.
The elm cultivar Ulmus minor 'Bea Schwarz' was cloned at Wageningen in the Netherlands, by the elm disease committee, from a selection of Ulmus minor found in France in 1939. However, specimens of the tree grown in the UK and the United States are falsely treated as Ulmus × hollandica.
The elm cultivar Ulmus 'Hillieri' arose from a chance seedling at Hillier's Pitt Corner nursery near Winchester, England, in 1918, and was marketed from 1928 as Ulmus hillieri, a name accepted by Christine Buisman in her 1931 labelling of a specimen in France. Since at least 1944 the tree has been determined a form of Ulmus × hollandica, its designation at Kew Gardens, in Green, and in later Hillier catalogues. In 1940, 'Hillieri' was noted as being a hybrid of uncertain origin. Krüssmann notes that for a time the tree was listed by Hilliers as U. × hillieri.
The hybrid elm cultivar Ulmus 'Den Haag' is a Dutch development derived from a chance crossing of the Siberian Elm cultivar Ulmus pumila 'Pinnato-ramosa' and the Belgian Elm Ulmus × hollandica 'Belgica'. S. G. A. Doorenbos (1891-1980), Director of Public Parks in The Hague, finding that seeds he had sown in 1936 from the Zuiderpark 'Pinnato-ramosa' had hybridized with the local 'Belgica', selected six for trials. The best was cloned and grafted on 'Belgica' rootstock as 'Den Haag'; it was planted first in that city, then released to nurseries elsewhere in the Netherlands. The other five were also planted in The Hague.
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 1869 catalogue as Ulmus montana nana. Henry (1913), referring his readers to an account of the Kew specimen in the journal Woods and Forests, 1884, 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.
The Siberian Elm cultivar Ulmus pumila 'Pendula' is from northern China, where it is known as Lung chao yü shu. It was classified by Frank Meyer in Fengtai in 1908, and introduced to the United States by him from the Peking Botanical Garden as Weeping Chinese Elm. The USDA plant inventory record (1916) noted that it was a "rare variety even in China". It was confirmed as an U. pumila cultivar by Krüssmann (1962).
The Siberian elm cultivar Ulmus pumila 'Pinnato-ramosa' was raised by Georg Dieck, as Ulmus pinnato-ramosa, at the National Arboretum, Zöschen, Germany, from seed collected for him circa 1890 in the Ili valley, Turkestan by the lawyer and amateur naturalist Vladislav E. Niedzwiecki while in exile there. Litvinov (1908) treated it as a variety of Siberian elm, U. pumilavar.arborea but this taxon was ultimately rejected by Green, who sank the tree as a cultivar: "in modern terms, it does not warrant recognition at this rank but is a variant of U. pumila maintained and known only in cultivation, and therefore best treated as a cultivar". Herbarium specimens confirm that trees in cultivation in the 20th century as U. pumilaL. var. arboreaLitv. were no different from 'Pinnato-ramosa'.
