I have one here in Zone 4 but it's in a pot that we bring into the basement for the winter. We've had it for many years. I think it will survive -5C (23F) but may be damaged at that temperature. That's my cut off temp for bringing it indoors. I'd expect much lower than that to be fatal. It is very easy to overwinter in the basement, if you have one. We keep it on the dry side. Dubious as a houseplant given its toxicity.
