Arum cornutum is an old name for Voodoo Lily. We most commonly now hear the name Sauromatum venosum, but I think it's been moved to Typhonium venosum. At any rate, they're all three the same thing.

Oh, didn't answer your question. I think they're reliably hardy to Zone 7, probably Zone 6 with protection.

Well Angie, I don't put mine outeside until I have some offfsets to experiement with. You can never tell, you could loose it. I always say, best to be safe. :) arum

Thanks guys for the fast responses.

Angie

My Voodoo lilies remain outdoors always. Also temperatures below zero ( °C) do not affect them.
only the flower remains somewhat smaller compared with indoor growing.
Gijs

Mine were planted outside about 5 years ago and have come back up every year, I'm in zone 7A.
The flowers have a disgusting smell to them which I was not aware of untill this spring. I guess that attracts the flys I saw that were all over them.