I live in Florida (Tampa) and have two cardboard zamias, that despite my efforts received frostbite. They are now a beautiful shade of bronze, but I know that's bad news for the future. They are large (4' in circumference), and I don't know what to begin doing to save them or if it's even possible.
Certified GKH Gardening Expert
I am sorry to hear about your plants. This article may help you with getting them to recover: https://www.gardeningknowhow.com/plant-problems/environmental/tips-for-saving-cold-damaged-plants.htm