lorax

I'd say go right ahead and buy those nannas! As Ms. Kitty notes it may take a few years for them to start fruiting, but in that time they'll probably set pups that you can separate off and use to start your banana grove. You're in a hot enough zone to stick 'em in the ground, and I'd reccomend you do it.

Gran Nain is a lovely cultivar and you'll find that once it gets going, the bananas it produces are great for both the rescue monkeys and your own consumption. It's one of the two main cultivars here in Ecuador for export bananas (the other being Cavendish.)

If they're in 2-gallon pots, you're probably about 3-4 years from fruiting. This said, they grow pretty fast and any banana, regardless of its initial size, is worth having in your landscape.

Betcha can't plant just one!