I love Cannas and they grow great out here in the country...I will be happy to pay the postage, but please let me send you something, too. This is too good to be true!!!! I want to do both...that is not fair to you!!!
Cannas are pretty easy. They do like moisture and some cow manure (composted) is good...they are heavy feeders. Full sun, but tolerate a bit of shade here in the heat.
The only major problem they have here is leaf rollers. You can see this if you have rolled foliage that won't open. Look carefully, and there would be little threads holding it closed. There would be little caterpillars inside if you opened it.
If you get these nasty buggers :), cut off the infected foliage and burn or trash it. Leaf rollers can overwinter in infected foliage and won't be killed off in a compost pile.
I've found that an insecticide is very effective in controlling leaf rollers, in addition to cutting off infected leaves.
I use an Ortho product called Bug B Gone Max. I'm considering spraying my cannas regularly as a preventative measure - I'm almost guaranteed to get leaf rollers if I don't.
Another problem to watch out for is rust on cannas. For some reason, Richard Wallace seem to be particularly prone to it. Unfortunately, it can't be cured, but spraying cannas with a fungicide will prevent the spread of it. If caught at an early stage, it won't be noticeable; again, preventive spraying is recommended.