If you are overwintering them in the ground, the stalks should be cut slightly below the surface and covered with a tarp and mulch to avoid pooling of water around tubers when they are completely dormant.

This may or may not work for you, depending on how cold it gets where you are as well as how wet the soil gets while tubers are dormant.

I am in zone 5-6 with lots of frozen earth, so I always dig. However, I did a fair amount of research on overwintering clumps in-ground, as some in this garden zone have been successful when plants were in a protected area like next to a house foundation or solid wall. One grower in zone 5 claims to overwinter regularly with tarps and mulch, but since tubers need to be dug and divided regularly anyway, it doesn't make sense to me to risk leaving them in-ground over winter.

Ok thank you. Guess i will dig up and research how to devide and store them!