Hello Joyce, Minimum 50 degrees F is the requirement mentioned in RHS Manual for Bulbs. Hymenocallis are generally tropics and sub-tropics plants. We don't have this kind of weather for much of our summer. (One of my Nigerian customers once asked me "How is it that you have rain in your dry season?") Hymenocallis x festalis and H. longipetala and H. "Sulphur Queen" can be kept through colder temperatures than this but they will go into dormancy, lose their leaves and must be kept dry. If you can keep them at Min 50F, the foliage will survive and you'll get better response in the following summer. Be interested to see how Bill keeps his over winter. Regards Hamish