I live in Toronto, on 15th floor of a condo facing west, getting plenty of light throughout the day. I have a potted hydrangea and I love it and want to care for it during winter, hoping to have it re-bloom in the next spring. Different sites give different suggestions. PLEASE advise!
Hydrangea Winter Care
Certified GKH Gardening Expert
Recommendations for winter protection depend on the lowest temperature that your region typically experiences each winter. In Toronto, it looks like some species (Hydrangea aspera and microphylla) do need protection because some nights reach below 0 degrees F but not below -10 degrees F. Additionally, potted plants are more sensitive to cold.
Recommended protection methods involve surrounding the plant and pot with a frame or metal cage, filling the cage to surround the plant with leaves or straw, then placing a plastic bag or row cover over the whole thing. Or, for potted plants, you can simply bring them indoors. Here is more: