One of the first things all gardeners learn about is plant hardiness and their zones. In an update from the 1990 version previously in use, the USDA has recently released a new Plant Hardiness Zone Map (PHZM). The new map promises greater accuracy and detail, and includes a “find your zone by zip code” function online. Of note is the shift of zone boundaries in many regions of the country. The new map is generally one 5-degree Fahrenheit half-zone warmer than the previous map throughout much of the U.S., though, in some cases, zone boundaries shifted to cooler temperatures.
For more information: http://planthardiness.ars.usda.gov/PHZMWeb/