I would guess probably zone 8, maybe the higher end of zone 7, idk forsure because it doesnt really get that cold here. The tree themselves seem to be hardy. But the leaves, especially the new leaves will burn with light to moderate frost. But when they are dormant frost isnt much of a problem as long as it isnt too cold.
Hope this helps a little.

- US_Marine

I have the dwarf variety that is basically grown for its flowers. This particular type is very cold hardy--at least to Zone 7a. Don't know about the typical variety--but my guess is zone 7a/7b, and remember, microclimates around the house can be much milder. Go for it!

I planted an Angel Red just over a year ago. It adapted easily and even gave me two fruits the first year that tasted pretty good. The trees are worth it for the flowers alone.

They do very well here at our beaches. The flowers are spectacular. Like an orange carnation. I've also seen verigated orange and white. I saw BIG fruiting ones down in Smith Island, Maryland out in the middle of Chesapeake Bay. Baseball sized fruit, that really caught me off guard!

Thanks for the info guys, I did purchase and planted it over the weekend. It would be very nice to have some to snack on in a few years :)