Why did we not plant Petunias in our window boxes and planters downtown?
Petunias do no handle heat well. They are extremely thermophotoperiodic. (Their growth habit responds according to the temperature and the amount of daylight.) At temperatures above 75 degrees plants will be tall and leggy with a single flower. The only Petunias that might work are Petunia x violacea 'Laura Bush' and 'Violet in Profusion'.