Bananas.org - Need Banana Advice

Hi Everyone,
I have some Cavendish Bananas in Pots that are doing good. They were potted 17 months ago. The P stem is about 9 ft tall. It has not bloomed yet. Any ideas on how I can get them to Bloom? Also, I planted some Gold Finger, Black Thai and Cavendish outside this last past spring. They are also growing well and sending up pups. I live in zone 7b/8a in south carolina on the coast. In the winter our temps are in the 40's, we will get a few frosts at night where the temp gets to 32 degrees. Maybe 5 times over the course of our winter which is from December to March or April. The wind in the winter is cold coming off the ocean. I am a block off the ocean. What I want to know is how to winter the Cavendish, Black Thai and Goldfinger. I tried to winter some over last year by muching them good but the Pstem rotted at the base. I did get some new pups off them in the spring but the were slow to grow. How can I keep the ones I have with out the Pstem dying off. I would like them to start growing next spring where they leave off this fall.
I truly appreciate in advice you can give me !!!
NannerLand