You could ask the Nevada Forum and see if they can help you out?

You posted your question quite some time ago, but perhaps you are still waiting for an answer. I'm a New Zealander...and know both pohutawaka & ponga.

Don't you get freezing temps in your area? Both plants do well in a climate like San Diego.....but I doubt you'd have much success in Nevada. Ponga is very frost tender - and I'm betting the pohutakawa is also. Pohutakawa will grow to be a huge tree. They line the beaches in New Zealand....also called, 'New Zealand Christmas Tree' as they bloom in December/January.