Yes! An article by Mike…
Apparently the Queen of Hearts from Alice in Wonderland was a dahlia grower, and she knew what to do with dahlias after the first hard frost. The day after the first hard frost hit, I went out and cut the stalks of all the dahlias. I left about 6 inches of the stalk sticking out of the ground.
Freezing will explode some the cells of the leaves of the plant and the liquid from the cells can run down inside the hollow stalk right back to the tuber. This load of water can increase the chance of root rot in the tuber during Winter storage, and that is not a good thing. Cutting the stalk will allow the tuber to keep its normal moisture content, a good starting point for saving the plants for next year. If you can’t remove the top portion when cutting, at least pull it to the side, away from the rest of the plant, so that water won’t drip back into the lower portion in the ground.
After cutting, allow the tuber to rest in place for 2 weeks. The plant just had its head cut off….the ultimate “bad hair day”. It needs a little time to get over the shock.
Sorry to have to tell you this…after that they all have to come out of the ground and get packed away for Spring.