What Tiffany said, + There is hope, but survival largely depends on how much stored energy the plant has. Surviving complete or near complete defoliation at this time of year requires that your has enough stored energy to provide energy enough to push a new flush of foliage to a point where a good % of the leaves are at least 75% mature, which represents the point at which the leaves become a net producer of energy, as opposed to a net consumer.
All tissues consisting of cells in which ice crystals have formed will lose viability, so you should expect a level of dieback anywhere from minor to complete, depending on just how cold it was and to some degree for how long. With any luck, the dieback will be limited to leaves only or to leaves and the more succulent tissues near branch apices (tips).
Al
