In my opinion, it's the potted trees that have really leafed out that you have to worry about the most. A few more cold nights here won't harm a tree that hasnt leafed out. But, given that we are only a few days or a week at most away from overnight freezing temps, might as well wait. Here in the greater DC area, calling for 26F tonight, but remainder is all on the up-n-up. Remainder of the week highs to be high 60s. Low 20's out right now this early Sunday morning, so nothing growing outside, and my outdoor figs are on hold.