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''Ulmus'' 'New Horizon' is an American hybrid cultivar raised by the Wisconsin Alumni Research Foundation (WARF), from a crossing of Siberian Elm ''Ulmus pumila'' (female parent) with Japanese Elm ''Ulmus davidiana'' var. ''japonica'' 〔Santamour, F. S., & Bentz, S. E. Updated checklist of elm (Ulmus) cultivars for use in North America. ''Journal of Arboriculture'', 21(3): May, 1995. ()〕 and patented in 1994. ==Description== Unlike its elder sibling 'Sapporo Autumn Gold', 'New Horizon' has a compact, pyramidal form, with comparatively dense foliage comprising glabrous, dark-green, elliptical leaves < 12 cm long by 7 cm broad, occasionally without the asymmetric bases typical of the genus. The perfect, apetalous wind-pollinated flowers appear in March, followed by the seeds in April; flowering usually begins when the tree is aged 8 years.〔Photographs of 'New Horizon' elms, () () and leaves, ()〕 The tree's growth habit is unusual; in an assessment at U C Davis as part of the National Elm Trial, its stem diameter increased faster than any other of the 15 cultivars, but increase in height, averaging a modest 0.9 m per annum, made it one of the slowest growing, vertically. In commerce in the USA, the tree is occasionally propagated by grafting onto an ''Ulmus pumila'' rootstock, rather than simply rooting cuttings as normally practiced in North America and Europe. More recently in the Netherlands, cuttings have been successfully grafted onto Belgian Elm rootstocks in the hope of making the tree more adaptable to heavy, clayey soils. Image: New Horizon leaf with Euro.jpg|Leaf, with 1 Euro coin. Image: Ulmus New Horizon (Quai Sainte Marie Chal.jpg|'New Horizon', Chalons-sur-Saône. Image: New Horizon trunk nobbles.jpg|Nobbled stem arising from regular removal of sideshoots. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ulmus 'New Horizon'」の詳細全文を読む スポンサード リンク
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