Ulmus minor 'Silvery Gem' | |
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Species | Ulmus minor |
Cultivar | 'Silvery Gem' |
Origin | Europe |
The field elm cultivar Ulmus minor 'Silvery Gem' is an ornamental clone raised, as Ulmus carpinifolia 'Silvery Gem', before 1965 by P. G. Zwijnenburg of Zwijnenburg nurseries, Boskoop, The Netherlands. [1]
A moderately tall growing shrub, reaching about 3–4 m (9.8–13.1 ft) in 10 years and with rather dense, twiggy branches bearing ovate leaves of a grey-green or silvery colour, especially in the spring, with irregular but conspicuous creamy-white margins. [2] The colouring and variegation are most striking in spring, fading somewhat in summer. [1] [3] [4]
'Silvery Gem' is not known to be resistant to Dutch elm disease,[ citation needed ] but the low height of the tree may ensure that it avoids colonization by Scolytus bark beetles and thus remain free of infection. It has been noted that shrub-elms are usually less prone to infection. [5]
The clone won a Golden Medal in The Netherlands in the mid-1960s. [1] It remains available from several nurseries in Europe (see below).
The field elm cultivar Ulmus minor 'Stricta', known as Cornish elm, was commonly found in South West England, Brittany, and south-west Ireland, until the arrival of Dutch elm disease in the late 1960s. The origin of Cornish elm in the south-west of Britain remains a matter of contention. It is commonly assumed to have been introduced from Brittany. It is also considered possible that the tree may have survived the ice ages on lands to the south of Cornwall long since lost to the sea. Henry thought it "probably native in the south of Ireland". Dr Max Coleman of Royal Botanic Garden Edinburgh, arguing in his 2002 paper on British elms that there was no clear distinction between species and subspecies, suggested that known or suspected clones of Ulmus minor, once cultivated and named, should be treated as cultivars, preferred the designation U. minor 'Stricta' to Ulmus minor var. stricta. The DNA of 'Stricta' has been investigated and the cultivar is now known to be a clone.
The Field Elm cultivar Ulmus minor 'Sarniensis', known variously as Guernsey elm, Jersey elm, Wheatley elm, or Southampton elm, was first described by MacCulloch in 1815 from trees on Guernsey, and was planted in the Royal Horticultural Society's gardens in the 1820s. It was listed in the Loddiges catalogue of 1836 as Ulmus sarniensis and by Loudon in Hortus lignosus londinensis (1838) as U. campestris var. sarniensis. The origin of the tree remains obscure; Richens believed it "a mutant of a French population of Field elm", noting that "elms of similar leaf-form occur in Cotentin and in northern Brittany. They vary much in habit but some have a tendency to pyramidal growth. Whether the distinctive habit first developed on the mainland or in Guernsey is uncertain."
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.
The Field Elm cultivar Ulmus minor 'Christine Buisman' was the first cultivar released by the Dutch elm breeding programme, initiated in response to the less virulent form of Dutch elm disease (DED), Ophiostoma ulmi, which afflicted Europe's elms after the First World War. 'Christine Buisman' was selected from a batch of 390 seedlings grown from seed collected in the Parque de la Quinta de la Fuente del Berro, Madrid, by Mrs Van Eeghen, a friend of elm researcher Johanna Westerdijk, in 1929 and named for the elm disease researcher Christine Buisman. Originally identified as Ulmus foliacea, it was later treated as Ulmus × hollandica by Melville. However, more recent research in Belgium using DNA markers has reaffirmed 'Christine Buisman' as a clone of U. minor.
The Field Elm cultivar Ulmus minor 'Viminalis Marginata', a variegated form of Ulmus minor 'Viminalis', was first listed as Ulmus campestris var. viminalis marginataHort. by Kirchner in 1864. Both Van Houtte and Späth marketed an U. campestris viminalis marginata in the late 19th century.
The Field Elm cultivar Ulmus minor 'Schuurhoek' was originally an old, nameless clone cultivated c.1880 in the vicinity of Goes, Netherlands, which was taken back into cultivation as 'Schuurhoek' by the van't Westeinde nursery at 's-Heer Abtskerke, Zeeland, in the 1950s. It was identified as U. carpinifolia by Fontaine (1968), though treated as a cultivar of U. × hollandica by some authorities.
The Field Elm cultivar Ulmus minor 'Propendens', described by Schneider in 1904 as U. glabra (:minor) var. suberosa propendens, Weeping Cork-barked elm, was said by Krüssmann (1976) to be synonymous with the U. suberosa pendula listed by Lavallée without description in 1877. Earlier still, Loudon's Arboretum et Fruticetum Britannicum had included an illustration of a pendulous "cork-barked field elm", U. campestris suberosa. An U. campestris suberosa pendula was in nurseries by the 1870s.
Ulmus minor 'Rueppellii' is a Field Elm cultivar said to have been introduced to Europe from Tashkent by the Späth nursery, Berlin. Noted in 1881 as a 'new elm', it was listed in Späth Catalogue 73, p. 124, 1888–89, and in subsequent catalogues, as Ulmus campestris Rueppelli, and later by Krüssmann as a cultivar.
The elm cultivar Ulmus 'Koopmannii' was cloned from a specimen raised from seed sent from Margilan, Turkestan by Koopmann to the Botanischer Garten Berlin c. 1880. Noted in 1881 as a 'new elm', it was later listed by the Späth nursery, catalogue no. 62, p. 6. 101, 1885, as Ulmus Koopmannii, and later by Krüssmann in 1962 as a cultivar of U. minor. Margilan is beyond the main range of Ulmus minor. Augustine Henry, who saw the specimens in Berlin and Kew, believed Koopmann's Elm to be a form of Ulmus pumila, a view not shared by Rehder of the Arbold Arboretum. Ascherson & Graebner said the tree produced 'very numerous root shoots', which suggests it may be a cultivar of U. minor. Until DNA analysis can confirm its origin, the cultivar is now treated as Ulmus 'Koopmannii'.
The Field Elm cultivar Ulmus minor 'Webbiana', or Webb's curly-leaf elm, distinguished by its unusual leaves that fold upwards longitudinally, was said to have been raised at Lee's Nursery, Hammersmith, London, circa 1868, and was first described in that year in The Gardener's Chronicle and The Florist and Pomologist. It was marketed by the Späth nursery of Berlin in the late 19th and early 20th centuries as U. campestris WebbianaHort., and by Louis van Houtte of Ghent as U. campestris crispa (Webbiana). Henry thought 'Webbiana' a form of Cornish Elm, adding that it "seems to be identical with the insufficiently described U. campestris var. concavaefoliaLoudon" – a view repeated by Krüssmann.
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 Elm cultivar Ulmus 'Tiliaefolia' was first mentioned by Host in Flora Austriaca (1827), as Ulmus tiliaefolia [:linden-leaved]. The Späth nursery of Berlin distributed a 'Tiliaefolia' from the late 19th century to the 1930s as neither an U. montana hybrid nor a field elm cultivar, but simply as Ulmus tiliaefolia, suggesting uncertainty about its status. Herbarium specimens appear to show two clones, one smaller-leaved and classified as a field elm cultivar, the other larger-leaved.
The Field Elm cultivar Ulmus minor 'Cucullata', the Hooded elm, was listed by Loddiges of Hackney, London, in their catalogue of 1823 as Ulmus campestris cucullata, and later by Loudon in Arboretum et Fruticetum Britannicum (1838), as U. campestris var. cucullata.
The Field Elm cultivar Ulmus minor 'Argenteo-Variegata' or simply 'Variegata', known in Australasia and North America as Silver Elm or Tartan Elm, is said to have been cultivated in France from 1772. Green noted that variegated forms of Field Elm "arise frequently, and several clones may have been known under this name". Dumont de Courset (1802) listed an U. campestris var. glabra variegata, Loudon (1838) an U. nitens var. variegata, and Wesmael (1863) an U. campestris var. nuda microphylla variegata.
The Field Elm cultivar Ulmus minor 'Umbraculifera Gracilis' was obtained as a sport of 'Umbraculifera' by the Späth nursery of Berlin c.1897. It was marketed by the Späth nursery in the early 20th century, and by the Hesse Nursery of Weener, Germany, in the 1930s.
The Field Elm cultivar Ulmus minor 'Microphylla Pendula', the Weeping small-leaved elm, was first listed by the Travemünde nursery, Lübeck, and described by Kirchner in Petzold & Kirchner's Arboretum Muscaviense (1864), as Ulmus microphylla pendulaHort.. By the 1870s it was being marketed in nurseries in Europe and America as Ulmus campestris var. microphylla pendula.
The Field Elm cultivar Ulmus minor 'Pendula' was said to have been raised in Belgium in 1863. It was listed as Ulmus sativa pendula by C. de Vos in 1887, and by Boom in 1959 as a cultivar.
The Field Elm cultivar Ulmus minor 'Rugosa' was distributed by the Späth nursery, Berlin, in the 1890s and early 1900s as U. campestris rugosaKirchner. Kirchner's tree, like Späth's a level-branched suberose field elm, was received from Belgium in 1864 as Ulmus rugosa pendula. Kirchner stressed that it was different from Loudon's Ulmus montana var. rugosa, being "more likely to belong to U. campestris or its subspecies, the Cork-elm".
The Field Elm cultivar Ulmus minor 'Suberosa', commonly known as the Cork-barked elm, is a slow-growing or dwarf form of conspicuously suberose Field Elm. Of disputed status, it is considered a distinct variety by some botanists, among them Henry (1913), Krüssmann (1984), and Bean (1988), and is sometimes cloned and planted as a cultivar. Henry said the tree "appears to be a common variety in the forests of central Europe", Bean noting that it "occurs in dry habitats". By the proposed rule that known or suspected clones of U. minor, once cultivated and named, should be treated as cultivars, the tree would be designated U. minor 'Suberosa'. The Späth nursery of Berlin distributed an U. campestris suberosa alataKirchn. [:'corky-winged'] from the 1890s to the 1930s.