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.
Suggested hardiness zones are included for each item in this catalog. For example, a plant's range listed at 4-9 means the plant is known to be hardy in zones 4, 5, 6, 7, 8, and 9.
Keep in mind that local variations such as moisture, soil, winds, and other conditions might affect the viability of individual plants. Urban areas and regions with bodies of water or mountains may contain climatic pockets that mirror warmer or cooler zones than the surrounding region. If it looks on the map like you should be in a different hardiness zone than the one we provide for you, you're likely in a microclimate too small to represent on the map.