The USDA Zone Map

    It really helps to know where you are in life! The USDA several years ago developed a horticultural zone map to let folks know where they fit in and what they can grow in their area of residence. The basic map lets you know how “cold hardy” a plant must be to be grown in your area. For instance, if you live in Richmond, VA, your hardiness zone is shown to be 7 on the map. That means that you can grow any plants rated for zones up to 7 with reasonable certainty of cold hardiness—usually they won’t freeze out on you. You can always run into a severe cold snap or climate combination that might kill your plants, but not usually.

    You can always try plants from zones 8 and 9, but normally these will not successfully over-winter in your area without significant accommodations—like a beneficial microenvironment (e.g., a warm south-facing brick wall to grow against) or wrappings of some sort on cold nights. We prefer to keep such plants in portable containers that can be plunged into the garden in spring and brought back into a cold greenhouse in the winter. In short, you gamble with it all, but your risks are lower if you stick with plants of the proper zone rating.

    A Special Note For WNC Mountain Folk. We now know by experience that Asheville is properly a zone 6A to maybe 6B rating. Further north in the mountains - Madison County, Spruce Pine etc. could be zone 5. Folks in Grandfather Mountain, Newland area think they are even a colder zone - maybe 4B! Hendersonville probably rates as 6B. Highlands Cashiers is colder again. These variations are due to elevation, wind patterns, temperatures, and exposure to the elements.

To download the U.S. zone map click HERE

To download the south east zone map click HERE

USDA Hardiness Zones and Average Annual Minimum Temperature Range

  Zone  
  Fahrenheit  
    Celsius    
  Example Cities  
1
 Below -50 F  
Below -45.6 C
Fairbanks, Alaska;   Resolute, Northwest Territories (Canada) 
2a
-50 to -45 F  
-42.8 to -45.5 C
Prudhoe Bay, Alaska;   Flin Flon, Manitoba (Canada) 
2b
-45 to -40 F
-40.0 to -42.7 C
Unalakleet, Alaska;   Pinecreek, Minnesota 
3a
-40 to -35 F
-37.3 to -39.9 C
International Falls, Minnesota;   St. Michael, Alaska
3b
-35 to -30 F
-34.5 to -37.2 C
Tomahawk, Wisconsin;   Sidney, Montana
4a
-30 to -25 F
-31.7 to -34.4 C
Minneapolis/St.Paul, Minnesota;   Lewistown, Montana
4b
-25 to -20 F
-28.9 to -31.6 C
Northwood, Iowa; Nebraska
5a
-20 to -15 F
-26.2 to -28.8 C
Des Moines, Iowa;   Illinois
5b
-15 to -10 F
-23.4 to -26.1 C
Columbia, Missouri;   Mansfield, Pennsylvania
6a
-10 to -5 F
-20.6 to -23.3 C
St. Louis, Missouri; Lebanon, Pennsylvania
6b
-5 to 0 F  
-17.8 to -20.5 C
McMinnville, Tennessee;   Branson, Missouri 
7a
0 to 5 F
-15.0 to -17.7 C
Asheville and surrounding areas, North Carolina;   South Boston, Virginia
7b
5 to 10 F
-12.3 to -14.9 C
Little Rock, Arkansas;   Griffin, Georgia
8a 
10 to 15 F
-9.5 to -12.2 C
Tifton, Georgia;   Dallas, Texas 
8b
15 to 20 F
-6.7 to -9.4 C
Austin, Texas;   Gainesville, Florida
9a
20 to 25 F
-3.9 to -6.6 C
Houston, Texas;   St. Augustine, Florida
9b
25 to 30 F
-1.2 to -3.8 C
Brownsville, Texas;   Fort Pierce, Florida
10a
30 to 35 F
1.6 to -1.1 C
Naples, Florida;   Victorville, California
10b
35 to 40 F
4.4 to 1.7 C
Miami, Florida;   Coral Gables, Florida
11
above 40 F
above 4.5 C
Honolulu, Hawaii;   Mazatlan, Mexico

A newer map rates plants on warm temperature extremes. I will have this one available shortly.

For more information on USDA zones please visit their site click here for a link