mikevan

In spite of the heat, I'd make sure you're not overwatering them. Overwatering will stunt nanners for certain. It's easy to water more when you see growth slow down for certain, but sometimes it's a matter of watering less. Feel the soil - it should be moist - but not sopping wet. Be sure that they've got good drainage and rather than daily watering, consider a thick mulch and a less frequent but deeper drip watering. For instance - my grapes in the currently hellish heat of Texas summer get watered very deeply every 4 or 5 days and they're practically jumping out of the ground. My nanners are containerized, but even then I only water them when their soil feels dry - usually every 3 days or so. Be sure to make sure they have plenty of organic matter and compost too. That's the best plant-food.

Good luck
Mike