Feed and water heavily. Altho it may be different for others, I've found that over the years the cannas planted into large planters usually seem to flower later than the ones in the ground. If your cannas are planted in smallish containers, I would move them to large ones. With the heat that we've been having, despite being in humongous planters, I've had to water them once (more often twice) a day as the container planters dry out really fast.

As far as the catapillars, I just squish them with my fingers. You could spray with Sevin but I've found that the squishing method is faster.

Jenna

You didn't mention if the cannas have been grown in this container previously. What I am about to ask is sometimes as the cannas multiply within the container there is inadequate room for soil and lots of roots form from the tubers. I have removed most of the tubers, move them out of the container and just plant a few in a new soil mix and it grows and blooms prolifically. Cannas are also heavy feeders. Hope this helps.

Vicki