Hardiness Zone Map

The hardiness zone map was created by the U.S. Department of Agriculture. The zones 1-13 are based on the average annual minimum temperatures for each zone. The United States is divided up into 26 zones (zone 1a through zone 13b). In the zone information given for each plant the smaller number indicates the furthest north that plant is expected to survive the winter. The larger number indicates the furthest south that the plant will perform consistently. Individual plants may be affected by local variation or a micro climate such as moisture, soil, winds, and other conditions.