Most hydrangeas need little care before winter. Most don't need fall pruning because spring buds form.
Hydrangea macrophylla is different. These are called mophead or lacetop hydrangeas, depending on their flowers
Once temperatures are consistently cold in USDA Zones 5 and colder, winterize big leaf hydrangeas
Water hydrangeas through the fall. If you don't get enough rain, you may need to water your new hydrangeas.
Mulch the area around them. This prevents soil from freezing and thawing, which can dry out roots.
If the containers are too large to move, hydrangeas can overwinter in place. Mulch and make sure the soil isn't dry before it freezes.