Plant heat tolerance information is difficult to obtain. Few references provide this information. The American Horticultural Society has developed a Plant Heat Zone Map that includes 12 zones based on the number of days the temperature rises above 86°F.

Many of our gardening books were written for English gardeners or for those in the northern section of the US. Plants that are reported to grow well in a cooler climate may or may not due well in the south. One of the biggest problems with temperatures in the south is warm nights. Plants produce food during the day and breakdown food (respiration) day and night. During cool nights respiration is slows but during hot nights respiration is significatenly higher. Thus high night temperatures cause lower food reserves.

Spruce, white pine, and lilac often develop diseases in the piedmont and coastal plain regions of our state because of the stress caused by long, hot summers. Delphenes usually do not preform well in the coastal plain or piedmont section of North Carolina.

Consumer Horticulture | Weather

© Erv Evans, Consumer Horticulturalist
Shoprights NC State University