Cannas like sun, lots of water, and regular feeding with a balanced fertilizer. Once the first spike of bloom on a leafy stem is done, it may still produce one or two more immediately below. Just cut off the first spike carefully, to make room for its successors, and, once they are all done, cut the whole leafy cane down to ground level, to make room for new canes with new spikes. When frost comes, dig up the rhizomes and store them in cool (12-17 deg. C) slightly moist conditions until planting again in spring. In the warmest exposures, they may survive the winter in the ground, but you will want to check with locals on that.