January 2018 issue of the Cornell Flower Bulb Research Program Research Newsletter:
Callas continue to be highly popular with growers and consumers alike. They grow well in a broad range of growing regions and you can’t beat the vividness and clarity of their colorful inflorescences. Like all plants, callas do have their environmental limits. Discussions with exporters have suggested a need to more carefully define high temperature maxima for callas. Commercial plantings in Florida, for example, have been observed to grow well in cooler areas of the greenhouse, while plants suffer in a hotter area of the same house.