These are probably Xanthosoma robustum, growing alongside bananas in St. Marys Georgia. These babies are about 7-8ft. tall but I have seen even bigger ones in South Florida.
Here is a link that might be useful:
Ummm, welllll, mine get that big here in North FLorida. The more water they get the bigger they get
Oh yes ive seen some giants in North Florida too. I can remember seeing them in Jacksonville as tall as houses. I probably should have said Florida in general instead of S. Florida.