To help you select the plants that prefer your climate, use the “Zones of Hardiness Map” published by the United States Department of Agriculture. This map divides the United States and Canada into 11 zones. Because winter cold is, in most regions, the single greatest threat to plant survival, the zones are divided according to the average monthly temperature they experience locally.
Plant descriptions in catalogs and labels typically refer to these hardiness zones to specify the areas in which any given plant will thrive. Once you have identified the zone in which your garden is located, purchase only plants recommended as reliably hardy there.
Note: If you plan to grow perennial vegetables, like asparagus and artichoke, you’ll need to identify your hardiness zone. Though your zone doesn’t necessarily dictate which annual vegetables, like tomatoes and lettuce, you can grow, it can inform you about which specific varieties will do best in your area.
USDA Plant Hardiness Zone Map
The 2012 USDA Plant Hardiness Zone Map is the standard by which gardeners and growers can determine which plants are most likely to thrive at a location. The map is based on the average annual minimum winter temperature, divided into 10-degree F zones.