USDA Plant Hardiness Zone MapThe US Department of Agriculture (USDA) has developed a system of zones that help us to determine which plants are best-suited to which areas of the country (sorry, I only have a map for the US here).  As this system of zones is pretty central to my plant selection process I’ve provided a link at the top of the page labeled “Zones” for quick reference.

The map of zones is divided into regions determined by their average low temperatures.  Within the lower 48 states we generally have zones 3 - 10, which are defined as follows:

  • Zone 10 - Low temps 30 to 40F
  • Zone 9   - Low temps 20 to 30F
  • Zone 8   - Low temps 10 to 20F
  • Zone 7   - Low temps 0 to 10F
  • Zone 6   - Low temps -10 to 0F
  • Zone 5   - Low temps -20 to -10F
  • Zone 4   - Low temps -30 to -20F
  • Zone 3   - Low temps -40 to -30F