The cultivar Ulmus 'Virens', the Kidbrook Elm, is an elm of unknown origin. It was first identified by Masters as U. virens in Hortus Duroverni 67, 1831, and later by Loudon in Arboretum et Fruticetum Britannicum, 3: 1376, 1838, as U. campestris (: minor) virens. Described in some detail by Elwes & Henry (1913) as a form of Field Elm but classified as U. × hollandica by Green, the tree is not mentioned in Bean's classic works on British trees.
The tree is distinguished by an upspreading crown, in mild winters retaining its foliage into December (Loudon called it "almost evergreen"). The leaves are oval, < 10 cm long by < 5 cm wide, long acuminate at the apex, and coarsely biserrate; the bark a distinctive red. The flowers are similar to those of Huntingdon Elm; the samarae are similar but smaller. Loudon thought the tree of possible Cornish origin, perhaps on account of its straight trunk, ascending branches and foliage, dark green until late in the year.
No specimens are known to survive. The Kidbrook Elm was reputed to have grown well on chalky soils, but its shoots were said to be vulnerable to autumn frosts. Henry recalls seeing only one specimen, at Ashwell Bury near Baldock, which he found resembled the Huntingdon Elm in many respects. A specimen leaf-spray and samarae from the Ashwell Bury tree are held in the Kew Herbarium. Henry reported 'Virens' apparently "unknown in nurseries" at the time of writing (1913). The reasons for its disappearance at the height of the 19th century elm vogue are unknown.
Pests and diseases
'Virens' is susceptible to Dutch elm disease.
Loudon reported a fine specimen in the Horticultural Society Garden, named U. montana nodosa (:'knotty').
- Ulmus campestris virens: Loudon, Arboretum et Fruticetum Britannicum, 3: 1376, 1838.
- Ulmus × hollandica 'Virens': Green,
- Ulmus virens: Masters, Hortus Duroverni 66, 1831.
- Green, Peter Shaw (1964). "Registration of cultivar names in Ulmus". Arnoldia. Arnold Arboretum, Harvard University. 24 (6–8): 41–80. Retrieved 16 February 2017.
- Bean, W. J. (1981). Trees and shrubs hardy in Great Britain, 7th edition. Murray, England.
- Browne, Daniel Jay (1846). The Trees of America: Native and Foreign. p. 480.
- Photograph of Ashwell Bury 'Virens' leaf and samara, apps.kew.org
- Elwes, Henry John; Henry, Augustine (1913). The Trees of Great Britain & Ireland. 7. p. 1896.
- Royal Horticultural Society (2012). Latin for Gardeners. Mitchell Beazley, London. ISBN 978-1845337315