On Zone 8, your only protection should be 3-4" of mulch through the drip line or so.

If the area is windy, you can extend the mulch a little more as windy weather tends to make wilting episodes more common. Some form of wind break (a structure, another plant, etc) might help if it is "too windy".

Hydrangeas should not need pruning if they are planted in a location where they can grow and not bump into other shrubs.

Luis