Hello Carol:
I look at plants in the nurseries and the tag says SUN, well, if I go by that I usually end up with a plant that wilts under most Florida sunny days. I do not want to water every day! So far I have found plumbago to be fine. I have usually bought a plant or plants and tested it for a summer and go by that...but that takes forever. Is there any really good source book for heat tolerance of plants?
Thanks,
Barbara
Port St. Lucie

Hello Barbara;
Good call, there is a big difference between full sun here on the Treasure Coast and full sun in other parts of the country. There are two good sources in my opinion for information on heat tolerant plants.
* Look for a listing of "Heat Zone" on the plant tag, this is very different from the USDA Zone Map. The Heat Zone map was developed by Dr Marc Cathey, President Emeritus of the American Horticulture Society and AHS owns the copyright for the map. For more information, visit http://www.ahs.org/publications/heat_zone_map.htm

* The other listing for planting for local conditions come from local colleges and universities. Here in Florida, that is the University of Florida. Some of the best publications for plants in our area are:
-----Low-Maintenance Landscape Plants for South Florida - http://edis.ifas.ufl.edu/EP107
-----Native Landscape Plants for South Florida - http://edis.ifas.ufl.edu/EP222
-----Landscape Tree Selection -- South Florida - http://edis.ifas.ufl.edu/TOPIC_Tree_Selection_South

Thanks for the question and Happy Gardening,
Carol