Ulmus 'Regal'
Ulmus 'Regal' is an American hybrid elm cultivar developed by the University of Wisconsin–Madison and released in 1983. 'Regal' was derived from seeds arising from the crossing of the Dutch hybrid clones 'Commelin' and '215' (Ulmus pumila × 'Hoersholmiensis') sent in 1960 by Hans M. Heybroek of the De Dorschkamp Research Institute in the Netherlands.
Description
'Regal' has a strong central leader bestowing an upright columnar form similar to 'Commelin', making it particularly suitable for street planting. The foliage is distinctively sparse, allowing dappled sunlight beneath the canopy . The leaves are narrowly elliptical, 5 cm to 10 cm in length, fern green when young, changing to a glossy, trichome-free, dusky spinach green. The perfect, wind-pollinated apetalous flowers emerge in early March.
Pests and diseases
'Regal' has a good resistance, rated 4 out of 5, to Dutch elm disease and verticillium wilt, but is very susceptible to the Elm Leaf Beetle Xanthogaleruca luteola in the USA. The tree's foliage was adjudged 'resistant' to Black Spot by the Plant Diagnostic Clinic of the University of Missouri .