Hardiness Zone maps are only a general indication of the areas in which plants are hardy. They may grow well in warmer zones, but not produce a suitable quantity of fruit, and the same is possible for colder zones. Micro zones may exist within a zone relative to elevation, northern and southern exposure, air, drainage, etc. Therefore, use the zones as a general indicator and rely more upon knowledge of blueberries that are growing in the area and horticultural recommendations.