A Classification of Hardy North American Apple Cultivars Based on Hardiness Zones

Abstract

In the past, apple cultivar hardiness has been predominantly reported as either a minimum survival temperature or in general descriptive terms, such as: tender, hardy, very hardy, and extremely hardy. When hardiness is reported as a specific minimum survival temperature, the researcher loses information on cultivar-environment mediated hardiness fluctuations. For example, if cultivar hardiness is characterized by a minimum survival temperature obtained in the fall or winter, no information is available to show that the injury might be due to a cultivar tendency to prematurely deharden in response to midwinter or early spring warm temperatures.