Editing Elm (section)

=== Propagation ===
[[File:White Elm rooted cutting.jpg|thumb|left|80px|A rooted cutting of European white elm (July)]]
Elm propagation methods vary according to elm type and location, and the plantsman's needs. Native species may be propagated by seed. In their natural setting, native species, such as [[wych elm]] and [[Ulmus laevis|European white elm]] in central and northern Europe and [[Ulmus minor|field elm]] in southern Europe, set viable seed in "favourable" seasons. Optimal conditions occur after a late warm spring.<ref name="Richens">Richens, R. H. (1983). ''Elm''. Cambridge University Press.</ref> After pollination, seeds of spring-flowering elms ripen and fall at the start of summer (June); they remain viable for only a few days. They are planted in sandy potting soil at a depth of 1&nbsp;cm, and germinate in three weeks. Slow-germinating [[American elm]] will remain dormant until the second season.<ref name="ReferenceA">forestry.about.com/od/treeplanting/qt/seed_elm.htm</ref> Seeds from autumn-flowering elms ripen in the fall and germinate in the spring.<ref name="ReferenceA" /> Since elms may hybridize within and between species, seed propagation entails a hybridisation risk. In unfavourable seasons, elm seeds are usually sterile. Elms outside their natural range, such as English elm [[Ulmus minor 'Atinia'|''U. minor'' 'Atinia']], and elms unable to pollinate because pollen sources are genetically identical, are sterile and are propagated by [[vegetative reproduction]]. Vegetative reproduction is also used to produce genetically identical elms (clones). Methods include the winter transplanting of [[Basal shoot|root suckers]]; taking hardwood cuttings from vigorous one-year-old shoots in late winter,<ref>{{cite web |title=Propagation: Root an Elm Tree Cutting &#124; DoItYourself.com |url=http://www.doityourself.com/stry/propagation-root-an-elm-tree-cutting |url-status=live |archive-url=https://web.archive.org/web/20131203103220/http://www.doityourself.com/stry/propagation-root-an-elm-tree-cutting |archive-date=3 December 2013 |access-date=2013-11-30 |df=dmy-all}}</ref> taking root cuttings in early spring; taking softwood cuttings in early summer;<ref>cru.cahe.wsu.edu/CEPublications/pnw0152/pnw0152.html</ref> [[grafting]]; [[layering|ground and air layering]]; and [[micropropagation]]. A bottom heat of 18&nbsp;°C<ref>resistantelms.co.uk/elms/ulmus-morfeo/</ref> and humid conditions are maintained for hard- and softwood cuttings. The transplanting of root suckers remains the easiest and most common propagation method for European field elm and its hybrids. For specimen urban elms, grafting to wych-elm rootstock may be used to eliminate suckering or to ensure stronger root growth. The mutant-elm cultivars are usually grafted, the "weeping" elms [[Camperdown Elm|'Camperdown']] and [[Ulmus glabra 'Horizontalis'|'Horizontalis']] at {{convert|2|–|3|m|ft|0|abbr=on}}, the dwarf cultivars [[Ulmus 'Nana'|'Nana']] and [[Ulmus × hollandica 'Jacqueline Hillier'|'Jacqueline Hillier']] at ground level. Since the [[Siberian elm]] is drought tolerant, in dry countries, new varieties of elm are often root-grafted onto this species.<ref name="Clouston">Clouston, B., Stansfield, K., eds., ''After the Elm'' (London, 1979)</ref> 
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Image:Ulmus minor MHNT.BOT.2010.12.3.jpg|Ripe samarae of field elm 
Image:Rock Elm seedling.JPG|[[Rock elm]] ''Ulmus thomasii'' germinating
Image:Klijavac ulmus glabra goc 0427.jpg|Seedling of wych elm ''U. glabra'' 
Image:Ulmus minor 14.jpg|Root-suckers spreading from [[Ulmus minor|field elm]] ''U. minor''
Image:Root cuttings of Ulmus 'Dodoens'.jpg|Root cuttings of [[Ulmus 'Dodoens'|''U.'' 'Dodoens']] 
Image:Elm clone rooted hardwood cutting Faculty of Forestry Belgrade 1983.09.01.jpg|Rooted hardwood elm cutting 
Image:Rooting of softwood cuttings of elm under the mist propagation system.jpg|Rooting of softwood cuttings under mist
Image:Ulmus campestris 'ARGENTEOVARIEGATA'.jpg|Mutant [[Ulmus 'Variegata' (Smooth-leafed Elm cultivar)|variegated smooth-leafed elm]] graft 
Image:Air layering of Ulmus pumila Faculty of Forestry Belgrade 7.6.1986.jpg|Air [[layering]] of [[Ulmus pumila|''U. pumila'']] 
File:Ulmus chenmoui in vitro.jpg|In vitro propagation of [[Ulmus chenmoui|''U. chenmoui'']] by bud [[meristem]] 
File:Ulmus (unknown cultivar). Royal Terrace, Edinburgh (5).jpg|[[Aerial root]]s, hybrid elm cultivar
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