Your hydrangea cutting may survive indoors but you need to provide a cool spot away from drying indoor heat. In its natural environment hydrangeas will lose leaves and go dormant in winter so that is what you want to suggest to your new cutting. Do not fertilize or water much during the winter months and keep near a cool window. A spot in an unheated but not freezing garage or shed is ideal. Do not let the potted cutting sit in drainage water and do not let the soil dry out. Just keep it barely moist. When you see signs of new growth in the spring you can bring the cutting indoors to a bright window and then move it back outdoors in early spring when the danger of a deep freeze has passed. Your cutting may have enough roots to be transplanted into the garden by early summer. Keep growing, Marianne Binetti