In my zone 6 sunset 3 area, I've seen a fair amount of canna plants in my neighborhood. After googling canna, these are generaly hardy to zone 7?
Are these bulbs that need to be dug up before winter sets in?
Ok, never mind. lol! I'm a budding yardener, not a gardener.
Sometimes they do come back in a marginal zone, in conditions that they find favorable, perhaps close to the foundation or a winter not overly harsh. Once you accumulate bulbs you can leave some in the ground to chance.
I love cannas, but I can't be bothered with digging them out of the ground. We have tulips that I've never dug out of the ground, yet they keep coming up every spring. I think I will chance it with canna.
Before we moved into our house we were viewing it in early spring and we noticed all the tulips. When we moved in in June of course they were all gone and I started my planting later that fall. By that next spring my poor Alaskan fern I planted was being pushed out of the ground and the tulips were growing through my fern! I thought I got all of them but I think I'm going to have to pull up the fern this year.