From experience I know that plants in planters need to be considerably hardier than plants in the ground. Plants that are hardy here in the ground have died when planted in a large planter. The freeze thaw cycles are hard on the plants, so they may not have survived, but I would not give up hope yet. For the future, I have found the plants in a container do better if they can be placed where the temperature is more even, such as in a garage or the north side of a building and buried in snow or completely surrounded by mulch or bags of leaves, etc.