The American Horticultural Society's heat-zone map looks much like the USDA map, with colorful swaths painted across North America. It shows that Charleston receives 60 to 90 days a year above 86 ...

Westerners may swear by the Sunset maps, but for most of the country the U.S. Department of Agriculture map of plant hardiness zones is the gold standard. Why hasn't it been updated since 1990? A ...

The AHS Plant Heat Zone Map identifies 12 zones, indicating regions where plants are subjected to high temperatures that could impact their growth, survival, and flowering times.

The American Horticultural Society (AHS) Heat Zone Map provides the annual average number of days in which the temperature is at least 86 degrees.

To order a copy of the AHS Plant Heat-Zone Map, contact: the American Horticultural Society, 7931 E. Boulevard Drive, Alexandria, VA 22308; (800) 777-7931; [email protected].

The American Horticultural Society developed its Heat Zone Map to provide information about plant response to heat. This map's 12 zones indicate the average number of days each year on which a ...