what plant zone is
The planting zones, also called hardiness zones, divide the United States, Mexico and Canada into 11 areas. Each of the gardening zones is based on a 10 degree Fahrenheit difference in the average annual minimum temperature. Planting Zones 1 and 2a, the coldest, represent Canada. The United States falls within zones 2 through 10. Hawaii and Mexico are represented by zone 11, the hottest zone.