Sorry to hear of your maple problem. It was wide spread and unusual to have such a late freeze. I have hundreds of Japanese Maples, most in containers, and most experienced some damage. Overall all they are okay. I lost a few, mostly from secondary problems associated with the freeze and affecting those that were more susceptible due to lack of timely cultural practices on my part. The problem that most worried me was pseudomonas resulting from freeze damage. As a precaution I sprayed my trees with copper hydroxide just prior to the onset of frigid temps. Some of mine sustained tip die back, the new tender growth was damaged. I was torn between a long tedious job of pruning the necrosis out or just letting the trees compartmentalize. I opted on the latter and things look okay. I would just supply adequate irrigation and supply a good fertilizer soon. Avoid hot fertilizers that incorporate muriate of potash a.k.a. potassium chloride in the blend. A complete fertilizer with a micro package such as Pennington Nursery & Landscape 14-7-7 has always worked well for mine. A liquid feed of something like Monty's or fish emulsion w/ kelp would be good. An organic granular such as Nature Safe Natural & Organic Fertilizers or ESPOMA would be good also. Feed the roots or more accurately, the soil micro organisms that make nutrients available to the plant. Humates are good and foliar feeding is also. Keep an eye on it and give it the necessary cultural practices as needed but don't over do it. Keep it watered and don't apply much fertilizer after...say July 15th. I am sure that there may be subsequent symptoms of freeze damage that will show up later. Good luck and check out this thread on the very same subject:
http://www.arboristsite.com/showthread.php?t=49995
