I shouldn't answer this post since I'm no expert on those, but I'd suspect that like some tropicals they may not be even tollerant of temperatures below sixty of seventy degrees for any lenghth of time and especially lows in the 30's. It's surprising that at one time , I used to think you could almost keep any tropical going all winter in the ground anywhere where temperatures didn't get below freezing all winter ,even with constant chilly winter temperatures, and of course we know that's not the case, and I'm recently discovering that some plants will not even survive cool winter temperatures, or at best will always go dormant, but come back in the spring. I'll do more research on the topic , but would suspect the precise answer might be hard to find , even on-line. As mentioned on the palm forums often , there are many heat loving palms that just barely survive even in south Florida, where winter chills are rare, and many of those don't survive at all in California. I see looking at one web-site, it says hardy to only zones 10-11 and that's strictly tropical, with no cool temperatures for winter.

I've got an E-lang tree in my front yard in the San Fran East bay area. ( didn't know what it was for the first few years ) It is approx 30 ft high and is the "belle" of the neighborhood due to it's fragrance. It has taken " a kickin " a few times when the temp got down to freezing for 2-3 days in a row in winter. It looses alot of leaves but seems to come back strong each spring.