If you're talking about the one at the bottom of the picture, it is not a Zebrina, but a Musa 'Siam Ruby.' The species is originally from Thailand and you can find more information about your plant
in the wiki here. I picked one up myself this spring at a nursery here in St. Louis.
Best of luck with your bananas in Iowa! I'm from Mount Vernon, but am going to school here in St. Louis, MO. Hmm....I don't ever remember them selling bananas when I was back in Iowa. Must be a recent thing. I got my first ones from a professor at Cornell College I was working for.