Ulmus pumila

Ulmus pumila L., the Siberian Elm, is native to Turkestan, eastern Siberia, Mongolia, Xizang (Tibet), northern China, India (northern Kashmir) and Korea . It is also known as the Asiatic Elm, Dwarf Elm and (erroneously) Chinese Elm. U. pumila has been widely cultivated throughout Asia, North America and, to a lesser extent, southern Europe.

Description

The Siberian Elm is usually a small to medium-sized, often bushy, tree growing to 10 - 20 m tall, with a trunk up to 80 cm d.b.h. The leaves are deciduous in cold areas, but semi-evergreen in warmer climates, < 7 cm long and < 3 cm broad, with an oblique base and a coarsely serrated margin, changing from dark green to yellow in autumn. The wind-dispersed fruit develops in a flat, oval membranous wing (:samara) 1 - 1.5 cm long and notched at the outer end . The tree is short-lived in temperate climates, rarely reaching more than 60 years of age, but in its native environment may live to between 100 and 150 years [http://www.northern.edu/natsource/TREESA1/Siberi1.htm].

Pests and diseases

The tree has considerable variability in Dutch elm disease resistance . Moreover, like many other elms in North America, it is highly susceptible to damage from many insects and parasites, including the elm leaf beetle Xanthogaleruca luteola [http://www.sunshinenursery.com/survey.htm], powdery mildew, cankers, aphids, and leaf spot. In trials in Italy, the species was also found to have a slight to moderate susceptibility to Elm Yellows. However, U. pumila is the most resistant of all the elms to verticillium wilt .

Cultivation and uses

U. pumila was introduced to North America by Frank Meyer [http://asaweb.huh.harvard.edu:8080/databases/botanists?id=131899] who, whilst in the employ of the USDA, made several collecting expeditions to the Far East. The tree was initially cultivated at the USDA Experimental Station at Mandan, North Dakota, where it flourished . It was consequently selected by the USDA for planting in shelter belts acoss the prairies in the aftermath of the Dustbowl disasters, where its rapid growth and tolerance for drought and cold initially made it a great success. However, the species later proved susceptible to numerous maladies. Attempts to find a more suitable cultivar were initiated in 1997 by the Plant Materials Center of the USDA, which established experimental plantations at Akron, Colorado and Sidney, Nebraska. The study, no. 201041K, will conclude in 2020.

The species has a high sunlight requirement and is not shade-tolerant; with adequate light it exhibits rapid growth. The tree is also fairly intolerant of wet ground conditions, growing better on well-drained soils. While it is very resistant to drought and severe cold, and able to grow on poor soils, its short period of dormancy, flowering early in spring followed by continuous growth until the first frosts of autumn, renders it vulnerable to frost damage.

As an ornamental U. pumila is a very poor tree, tending to be short-lived, with brittle wood and poor crown shape, but has nevertheless enjoyed some popularity owing to its rapid growth and provision of shade. The Siberian Elm has been described by Prof. Michael Dirr as "one of, if not the, world's worst trees...a poor ornamental that does not deserve to be planted anywhere" . Yet in the USA during the 1950s, the tree was also widely promoted as a fast growing hedging substitute for Privet, and as a consequence is now commonly found in nearly all states . In the UK, its popularity has been almost exclusively as a bonsai subject, and mature trees are largely restricted to arboreta. Introduced into Spain in the 16th century, and later Italy, it has naturally hybridized with the Field Elm U. minor. In Italy it was widely used in viniculture, notably in the Po valley, to support vines until the 1950s, when the demands of mechanization made it unsuitable. Invasiveness
In North America it has become an invasive species from central Mexico [http://www.jstor.org/stable/2807778?seq=1] to Ontario. It is found in abundance along railroads and in abandoned lots and on disturbed ground. The gravel along railroad beds provides ideal conditions for its growth: well-drained, nutrient poor soil, and high light conditions, and these beds provide corridors which facilitate its spread. Owing to its high sunlight requirements, it seldom invades mature forests, and is primarily a problem in cities and open areas . In South America, the tree has spread across much of the Argentinian pampas .

Subpecies & varieties

One variety is recognized: var. arborea Litv..

Cultivars

Valued for the high resistance of some clones to Dutch elm disease, over a dozen selections have been made to produce hardy ornamental cultivars, although several may no longer be in cultivation: Ansaloni, Aurescens, Chinkota, Dropmore, Green King, Hansen, Harbin, Manchu, Mr. Buzz, Park Royal, Pendula, Pyramidalis Fiorei, Variegata

Hybrid cultivars

The species has been widely hybridized in the USA and Italy to create robust trees of more native appearance with high levels of resistance to Dutch elm disease: Arno, Cathedral, Coolshade, Fiorente, Homestead, Lincoln, Ulmus 'Morton Plainsman', Ulmus 'Morton Stalwart', Ulmus New Horizon, Plinio, Regal, Rosehill, San Zanobi, Urban, Willis.
Also U. '260' (Ulmus × hollandica 'Vegeta' × Ulmus pumila) raised at Wageningen but never commercially released; a few specimens survive as part of the Brighton & Hove CC NCCPG Elm Collection at Happy Valley Park, Woodingdean; Crespin Way, Hollingdean (10 trees), The Highway, Moulsecoomb (1 tree) and Royal Pavilion Gardens (1 tree).

Accessions

North America
Arnold Arboretum. Acc. nos. 17923, 638-79, 673-87.
Denver Botanic Gardens. Acc. no. 900534.
Dominium Arboretum, Ottawa, Canada. No acc. details available.
Holden Arboretum. Acc. nos. 99-868, 72-218
Longwood Gardens. Acc. no. 1962-0512.
Morton Arboretum. Acc. nos. 542-49, [http://www.cirrusimage.com/tree_Siberian_Elm.htm 325-70], 53-74, 172-U.
UBC Botanical Garden and Centre for Plant Research. Acc. no. 027560-0284-1989.
Europe
Arboretum of Warsaw University of Life Sciences [http://arboretum.sggw.pl/wykaz_u.html], University of Life Sciences, Warsaw, Poland. 2 trees, no accession details available.
Brighton & Hove City Council, UK, NCCPG Elm Collection[http://www.brighton-hove.gov.uk/index.cfm?request=c1108042].
Dubrava Arboretum, Lithuania. No details available.
Grange Farm, Sutton St. James, Spalding, Lincolnshire, UK. Acc. no. 521.
Hergest Croft Gardens, Kington, Herefordshire, UK. One tree, no accession details available.
Hortus Botanicus Nationalis, Salaspils, Latvia. Acc. nos. 18162,3,4.
Mote Park, Maidstone, UK. UK champion 22 m high, 66 cm d.b.h. in 1995. .
Royal Botanic Garden, Wakehurst Place, UK. Acc. no. 2000-4449.
Tallinn Botanic Garden, Estonia [http://www.tba.ee/index.php?lang=eng]. No accession details available.
Thorp Perrow Arboretum, Yorkshire, UK. British Champion tree, 19 m high, 70 cm d.b.h. in 2004 .
Westonbirt Arboretum [http://www.forestry.gov.uk/forestry/infd-62qk8w],Tetbury, Glos., UK. Two trees planted 1981, no acc.details.
Australasia
Alma Park, St Kilda, Victoria, Australia. One specimen, listed on the National Trust of Victoria's Significant Tree Register.
Eastwoodhill Arboretum [http://www.eastwoodhill.org.nz/gardens--collection/collection.aspx?Type=&G=Ulmus], Gisborne, New Zealand. 2 trees, details not known.

Nurseries

North America
Cumberland Mountain Nursery, Beersheba Springs, TN. [http://www.cumberlandmountainnursery.com/]
Mingo Nursery, Winchester, TN. [http://www.mingonursery.com/]
Europe
Arboretum Waasland [http://www.arboretum-waasland.be/English.htm], Nieuwkerken-Waas, Belgium.
Beeches Nursery, Saffron Walden, UK, [http://www.beechesnursery.co.uk].
Jardineria Sils [http://www.jardineriasils.com/productes.asp?ordre=u], Sils, Girona, Spain.
Norfields, Usk, Monmouthshire, UK, [http://www.norfields.co.uk].
UmbraFlor [http://www.umbraflor.it], Spello, Italy
Weasdale Nursery, Kirkby Stephen, UK, [http://www.weasdale.com].
Australasia
Established Tree Planters Pty. Ltd., Wandin, Victoria, Australia. [http://establishedtrees.com.au]

Seed suppliers

B and T World Seeds, Paguignan, 34210 Aigues-Vives, France [http://www.b-and-t-world-seeds.com/alaCart.asp]
Chiltern Seeds, Bortree Stile, Ulverston, Cumbria, LA12 7PB, England [http://www.chilternseeds.co.uk]
Lawyer Nursery, Montana Highway, 6625 West Plains, MT., USA [http://www.lawyernursery.com/maggies/specsd.htm]
Sandeman Seeds, 7 Route de Burosse, 64350 Lalongue, France [http://www.sandemanseeds.com/acatalog/Trees_and_shrubs_Ulmus.html]
Sheffield's Seeds Co. Inc. [http://www.sheffields.com/products/simple_search], New York, USA.

Translation

The phrase "Ulmus pumila" occurs as such in the following languages: English, French, Italian.

Translation(s) in other languages: Catalan: Om de Sibèria, Korean: 비술나무, Hungarian: Turkesztáni szil.