I don't think that they need a dormant period. Just keep in mind that they are agresive and need constant trimming back or soon you will have a cattail pond not a tropical one. I have to do this in a cold area pond so in a warm one they will grow fast.

Thanks aquawise. After posting here I also found the bog-garden group where there seemed to be a little more discussion on dwarf and other oddball cattails. One stated the dwarves were native to Siberia and linked to a grower who stated there were reports the plants needed freezing period to bloom. But nobody saying for sure yes that's the case! So I'm thinking maybe I need to set up a a bog outside for pitcher plants and cattails, in containers not a free-soil bottom so the growth is controlled and requires less "hands on" management than you speak of. And then I'd have to refrigerate or freeze the tubers in winter, because it never actually freezes in our yard.

Sounds like a plan. You could test them and just see if they need freezing to flower. They my just need to be cut down after flowering to start over?????? If you have a ready supply out side this my be worth a try.

I have a dwarf cattail in a pot that is a floating planter. It has been there for two years and basically stays the same. I guess because it can't go anywhere else. Being in Florida no dormancy but no flowers yet either.