‘Prairie Shade’ Elm

Abstract

Abstract Since the urban population of American elms (Ulmus americana L.) was ravaged by Dutch elm disease fungus [Ceratocystis ulmi Buism. (C. Moreau)], attention has focused on the development of disease resistant elm hybrids. The cultivars ‘Sapporo Autumn Gold’, ‘Urban’, and ‘Regal’ are highly resistant to Dutch elm disease (7, 8, 9); however, they are extremely susceptible to the elm leaf beetle, (Pyrrhalta luteola Muller), because the susceptible Siberian elm Ulmus pumila L.) is a common parent (10). On the other hand, Ulmus parvifolia Jacq. (syn. U. sempervirens), U. chinensis Pers., sometimes listed incorrectly as the lacebark elm (syn. leatherleaf elm, Chinese elm) is highly resistant to Dutch elm disease and the elm leaf beetle (1, 2, 4, 10). Lacebark elm is native to central China, Japan, and Korea, is drought tolerant, and withstands the severe conditions often associated with urban sites (10). Like most other members of the genus Ulmus, lacebark elm is propagated by seed collected in the fall; however, Schopmeyer (6) indicated that less than 50% of the seeds are viable, and only 5% to 12% of the viable seed sown can be expected to produce saleable trees. Four asexually produced cultivars, ‘Sempervirens’, ‘Drake’, ‘True Green’, and ‘Dynasty’ (5), currently sold provide improved consistency and quality.