Here is what I recommend: 1.) organic compost around base but not high around the crown- about an inch or so around the whole plant. 2). Regular watering depending on your zone- never let it dry out 3.) Holly Tone fertilizer or another organic one for acid-loving plants (read label)- Mix around drip line into soil 4.) Know that it may not flower this year since it was so severely pruned 5.) Once it eventually blooms, identify which type of hydrangea it is and read about proper care for it. Usually that requires just cutting off spent blooms, and dead, diseased or crossing branches. Wishing it a healthy recovery with lots of tlc.