I planted 11 dahlias and most are in full bloom. Gorgeous. I will post pics from home. I don't know how they will take our heat here in the Phoenix area. With regular watering morning and evening, do I just leave them in the ground as a perennial or dig them up? Thanks!
I'm in Zone 10 and I don't have to. I inadvertently did dig because I only had a few and had to make room for a hundred this year. But it wasn't till after winter that I accidentally dug them up and they all made it through a very cold (for us-several freezes), wet winter. So, I'm sure you'd be fine if you left them, just cover well with mulch. Don't forget to mark them-like I did. Ended up with a whole big batch of NOIDs because of it!
I've had Dahlias for 3 years now in Tucson, and I've never dug them up in winter. They get morning sun and afternoon shade but still require a little extra water in this heat. I love them- plan to plant more and more!
Poochella did describe the process really well - and I can speak from experience that if you do not lift and divide, dahlias will weakened and sometimes die out and disappear after 4-5 years. I lived in a mild climate and did not think I needed to dig up the tubers at all either.