Important dahlia question.
I had never tried dahlias and a friend of mine last year gave me 50 dahlias. I planted them all, and they were beautiful all season. I was told since my zone is 7A I was suppose to take them up but was too busy with work to do so. I didn't even mulch them. I have been preparing my beds for the season and have noticed quite a few are coming up. The beginning of winter was warm, but the end was very cold. Am I just lucky, or should I have heavy mulched them. Any advice for this year.