I'd definitely start them now -indoors or someplace warmer outdoors. I have canna started in a shallow pot that's doing well in a sheltered area on the south side of my house. If temps fall much below 45 I bring them into a warmer place. We had 34 degrees and frost overnight so I set them in a working compost pile with a cover over them. They were nice and toasty-warm this morning.
I need to get my caladium started too!
