Hardiness Zones

Plant Hardiness Zones divide the United States and Canada into 11 areas based on a 10 degree Fahrenheit difference in the average annual minimum temperature.

Hardiness zones are a guide used to determine the minimum temperature at which a particular plant will grow. Plants are often described as either being hardy to a particular zone (Hardy to Zone 5), or have a hardiness range (Hardy to Zones 5–9).

Take note that hardiness zones only tell the average minimum temperature. Many areas exist within Hardiness zones that have different average minimum temperatures than the hardiness zone indicates. These areas are referred to as microclimates. Microclimates can occur within cities or areas of your yard surrounded by warmth from houses, fences or walls.

USDA Hardiness Zones

Zone 1: below -50° F (below -46° C)
Zone 2: -40 to -50° F (-40 to -46° C)
Zone 3: -30 to -40° F (-34 to -40° C)
Zone 4: -20 to -30° F (-29 to -34° C)
Zone 5: -10 to -20° F (-23 to -29° C)
Zone 6: 0 to -10° F (-18 to -23° C)
Zone 7: 10 to 0° F (-12 to -18° C)
Zone 8: 20 to 10° F (-7 to -12° C)
Zone 9: 30 to 20° F (-1 to -7° C)
Zone 10: 40 to 30° F (4 to -1° C)
Zone 11: above 40° F (above 4° C)