My Hydrangeas are wilting too. They look better when the sun goes down. It's normal. I water them about twice a week. Mine died to the ground this year too but are starting to bloom. I have Hydrangea 'Twist 'n Shout' which normally blooms twice but this year it is only blooming once. My double Hydrangea called Forever and Ever 'Together' died to the ground too. Both of these bloom on new wood and old wood.
I wouldn't give up on them yet.
