Care of Hydrangea during winter time
How we can take care of the hydrangea during winter time? We have them out at the terrace on a 10th floor in Manhattan, NY where it is freezing out there. :(
You do need to protect them if you want them to survive the winter. Wrapping foam insulation around both pots and plants will help. This article has more information: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/hydrangea-winter-care-how-to-protect-hydrangeas-from-winter-cold-and-wind.htm
If you search for something like "terrace gardening experts in New York City," you should be able to track down someone who would have the best materials and techniques for accomplishing this task for you.