From the ArcaMax Publishing, Gardening Newsletter:
http://www.arcamax.com/news/gardening/s-1892-681571
Question: Last winter deer severely damaged my hollies--they removed
almost every leaf. I cut the shrubs back considerably this spring.
Several smaller shrubs recovered quite well, but the larger shrubs
still look sickly. Can I do anything to help them recover?
Answer: While most hollies will take some pruning and even tolerate
shearing well, drastic defoliation is a serious problem because it
takes so much of the plant's energy to sprout the replacement leaves.
As you have noticed, different varieties of holly may respond
differently, and younger wood will regenerate faster than older growth
can. Well established plants will recover faster from stress than
newly planted shrubs. Eventually they should fill in to be symmetrical
again as long as the branches are sprouting new growth.
If there is any dead wood on the plants, remove it any time. If there
are occasional stray branch tips reaching way out of line, nip them
off also. A light shearing can also be done. You will notice over time
that the branches become bushier where you have cut, so keep this in
mind as you decide where to make your cuts. However, since the setback
was so severe I am tempted to suggest leaving any extra growth to
supply energy to the plant to add in regaining vigor and then trim it
back as hard as necessary early next spring.
To help your hollies stay as healthy as possible, be sure they receive
adequate water throughout the growing season, consider using an
antidessicant spray this winter, and consider applying compost
annually. Consider a soil test to be sure the pH is acidic enough.
Finally, if at all possible protect them from the marauding deer. You
will probably need either a fence or some sort of cage around the
hollies. Some gardeners report success with repellent sprays and with
assorted home remedies, but if the browse pressure is severe as it
appears to be, the only truly reliable protection in my experience is
a physical barrier.
Good luck with your shrubs!