hydrangea

Leave until the spring, cutting back anytime before April promotes growth which will get frosted in the winter.
The only thing I would do is to clean out the old leaves from the shrub, leaving old flower heads on (when you have some) this protects the undeveloped flower heads for next year.

Hydrangea macrophylla do not normally need any pruning other than to remove the old flower heads as suggested.
Hydrangea paniculata may be cut back to a few inches above ground in February.
Ditto H. arborescens.
All the others need no pruning except to remove dead branches and old flower heads.