I am a total rookie when it comes to any plant. I bought 5 potted dahlias this summer and have kept them in their 5 gallon pots for the last 3 months. They are about 4' tall and have given me dozens of large blooms each. I live in a cold climate so I am not going to ever be planting them in the ground. Next summer I plan to move them to a slighly larger pot. I have been give some conflicting advice, so any experienced advice would be greatly appreciated. The first advice that I received is to just cut them down to 6" 1 week after the first frost and move the pots into my garage and leave them there. The folks at my local nursery say that is all they do and the tubers are just fine and come back for several years before requiring any splitting. Others have told me that I need to remove them from the soil, wash them, dry them, and store until spring (i have read several of the articles and understand the process but I am nervous about killing them). My preference would be to just leave them in their current pots for the winter because that seems very easy. If I do this will it kill them? What is the advantage of digging them up in fall if I don't have to? What is the survival rate of the tubers if I dig and divide and follow the instructions to a T? Thank you.