It may. It would help to know what type of hydrangea do you have, not to mention what zone you are in. I just bought a batch of Quickfire on sale, which I was quite enthused about as well. Placing a layer of several inches of mulch around the entire rootball would help. Perhaps even surrounding the plant with a tomato cage or similar apparatus filled with leaves would help as well. The goal will be to protect the plant from freeze/thaw and wind damage. Still, much of the plant could be killed back during a harsh winter, but new shoots may emerge from the ground if well protected.

If you experience cold winters (Zone 6 pr colder), another option is to keep the plants potted in a garage, water them once every 1-2 weeks and plant them in the ground about 2 weeks after your area's average date of last freeze. Do not fertilize them now; the potting medium probably already has those round fertilizer pellets anyways.