Hydrangeas are shrubs that adapt well to containers but you must check the soil with your finger and water enough to keep it moist but not soggy. This could mean every day during a warm spell or in a small pot or once a week during cooler weather or not at all if it is rainy. Hydrangeas like morning sun and afternoon shade and will wilt in hot sun no matter how much you water. Hydrangeas can stay outdoors all winter in most climates depending on the variety. Let me know what type of hydrangea you have and where you garden and I can  be more specific on winter protection. Keep growing, Marianne Binetti