LOL, I'm not sure what the lowest temp's are that they can withstand. I had two Cyathea cooperi for a few years and lost them to a winter freeze ... hoped they would re-appear but they never did. Everything I've read says they will take frost and lose their fronds but they re-emerge when the weather warms. I'm not sure why mine never sprouted new fronds. Oh how I'd love to have one about 25' tall.
They are just beautiful!
According to Wikipedia:
http://en.wikipedia.org/wiki/C... it has apparently become naturalized in parts of Australia; and in Hawaii it has become an invasive.
