What are Hardiness Zones (Plant Hardiness Zones)?
Growing regions designated by the US Department of Agriculture (USDA) which divides the United States and southern Canada into 11 planting zones based on a 10 degree Fahrenheit difference in the average annual minimum temperatures. Using these zones as a guide, seed companies and nurseries label their horticultural products based on which zones plants will grow most successfully in. Higher numbered zones are generally warmer.
