Best thing I have done for the banana, taro guild is ash. Either from charcoal or wood. It makes them go from average to giant in about a month. I have piled mulch, kitchen scraps, chop & drop, compost, chicken mature, 10 10 10, miracle grow and any other source of food I can throw at them but never had results like ash. It is like turning on the growth switch. Always lots of water, they love water.
During our wet season, Taro grows in the ditches here.