Question
I have 2 large ficus trees (25 feet tall) that got completely frostbit in January.  All the leaves are completely brown and falling off.  I heard that you should not do anything until spring, but what should I do and when exactly?

Answer
There is really not anything you can do except wait and see if the tree is dead. It should put on new foliage this spring. The new may come as new sprouts from the root system. The upper portions of the tree may have been killed by the frost. I would expect to see new growth from the roots and the older stem dead and after the sprouts appear prune the old dead off.