You did not say where do you live or the type of hydrangea so my "general answer" would be to maintain the soil well mulched and as evenly moist as possible with a sprinkle of fertilizer (a 1/4 to 1/2" of compost or composted manure is fine) spread up to the drip line. Not sure yet why leaf out is a problem. At worst, I would expect growth from the base but, that usually indicates that it needs winter protection. Some mopheads and lacecaps cannot handle the cold winters by themselves and need aid to releaf. Other hydrangeas are more winter hardy and well suited to the cold. They either releaf fine or when they leaf out from the crown, they bloom on new wood or rebloom from old/new wood so you always get bloomage. The dry looking sticks can be pruned by the end of May if nothing leafs out. If they leaf out partially, you can prune above the top leaves.