If I were going to get a killing frost, I'd just cut the branches down and put them in a vase like cut flowers. Then I'd keep them under fluoros to ripen a bit more. Every few days, change the water to prevent bacteria building up and clogging the tubes that drink in the water. If your water gets cloudy, cut a little bit off the end of the stem of your "flowers" and clean the vase and add new water. It should buy you a couple of weeks of ripening time.