Hm, depends on which type they are. If they're the ones that get to be the size of a Volkswagen, then yes, they shouldn't be so close to the banana.
If they're a smaller type, then it looks like they'll be far enough away for the nanner to get established. Then it will crowd them out eventually.
Word of advice on the 'big picture' if I may? Choose types of plants that don't get quite so big! Look at tags before you buy, and check how big it will be - most tags say "mature size 24in. to 30in". Bigger than that, leave it until you have a bigger garden. Believe me, you can attain the lush tropical look even with smaller plants if they are growing well. Trying to crowd bigger plants in will just keep frustrating you.
