Give them one more year to make more pups, then divide your Zebrina
pretty much like a day lily or daffodil -- any sort of clumpy thing.
Bananas are a giant herb. You can't kill them, even when you really want
to. Put them in a bigger pot, if you're afraid of crowding them. Check
out Brundy's Tropicals out of Houston for all the real technical stuff
on growing Zebrina.