Ulmus 'Urban'

Ulmus ‘Urban’ (Elm ‘Urban’, synonyms Ulmus ‘Ohio Hybrid’, Ulmus ‘No. 1’, Ulmus ‘Delaware No. 1’) originated from a cross between the Dutch clone Ulmus No. 148, sent to America by Dutch phytopathologist Johanna Went in 1952, and Ulmus pumila. Johanna Went took over from the also Dutch phytopathologist Christine Buisman after the latter's death in 1936, in researching disease-resistant elms. The cross was created in 1952 by US researcher Toru Arisumi and published in 1976 by the Agricultural Research Service experiment station in Delaware, USA. As a young tree, Ulmus ‘Urban’ makes a continuous heart branch and forms an upright, narrow and densely branched crown that becomes broad, irregular and rounded in later life. ‘Urban’ grows 15 to 20 metres high and 10 to 15 metres wide.

The shiny dark green, toothed leaf of Ulmus ‘Urban’ is ovate with a typical asymmetric leaf base, turning to a deep golden yellow in autumn. This elm is one of the first elms to show autumn colour in autumn. The crown has relatively thin wood and light grey twigs, the bark is also grey and remains smooth for a long time. Ulmus ‘Urban’ flowers in March with inconspicuous, red-brown flowers, they are followed by the typical nut fruits with samaras in the shape of doubles.

Back in 1974, tests were carried out with this elm in the Netherlands to see how it stands up in the Dutch climate. 'Urban' is moderately resistant to Dutch elm disease, in that respect comparable to Ulmus x hollandica “Commelin”. Compared to other elms, the growth of Elm ‘Urban’ is modest and partly for that reason this tree requires very little maintenance. In poorer soils and drought conditions, ‘Urban’ performs fine; in wet clay soils there is a risk of root rot. Wind, sea wind and air pollution are no problem at all. For well-chosen locations in a wide profile or landscape setting, Ulmus ‘Urban’ is therefore a beautiful elm, provided it is planted in small numbers so that disease does not prevail.