Tree lilac (Syringa reticulata) cultivars tested as street trees: Second report

Abstract

Through the Municipal Tree Restoration Program, cooperators planted three tree lilac (Syringa reticulata) cultivars in 13 Pennsylvania and New York, U.S. communities for evaluation as street trees, comparing two in each community. Standardized measurements in years 1, 2, 3, 6, 9, and 12 revealed that 'Ivory Silk', 'Regent', and 'Summer Snow' grew well and remained healthy at all locations. Average heights of the cultivars in the 12th year ranged from 4.8 to 5.1 m (15.8 to 16.8 ft). Differences in average height and crown width were small. In one community, the tallest cultivar, 'Ivory Silk', attained an average height of 6.4 m (21.1 ft) in the 12th year. 'Summer Snow' grew more slowly in height initially, and 'Regent' had narrower crowns. Foliage health ratings were somewhat lower than those of other species in some years, probably reflecting earlier yellowing of leaves in the autumn. If the tree lilac cultivars continue to grow at the same rate, they would not grow into overhead utility wires until the 18th year or later. © 2007 International Society of Arboriculture.