While many Heucheras are native to the west coast and are not tolerant of hot humid conditions, there are several species that are native to the east coast and can tolerate the heat and humidity of our southern gardens. Many modern Heuchera hybrids include these eastern species (including americana and villosa) in their parentage. As a result, these hybrids can grow in our hot and humid southern gardens if we give them the perfect growing conditions.
It is important to remember that these hybrids tolerate hot humid conditions. They do not thrive in these conditions. Heucheras prefer cool night temperatures and the best growth and color will be experienced in the spring and fall when we experience cool night time temperatures. However, give them the following conditions and they will survive our brutal summers:
Give Them Perfect Drainage
Let Them Dry Out Between Waterings
Dont Fertilize During the Summer Heat
Transplant and Reset Your Heucheras Every Few Years
Grow Heucheras in Slightly Acidic Soil