Preanthesis changes in freeze resistance, relative water content, and ovary growth preempt bud phenology and signify dormancy release of sour cherry floral buds.

Growing degree hours (GDH) predicted floral bud development of 'Montmorency' sour cherry and explained changes in lethal temperatures (LT) that preempted any visible changes in bud phenology. The gradual warming during late winter and early spring promotes floral bud development and, concomitantly, the de-acclimation of Prunus sp. flowers.