Deer browsing on only the green foliage of the Arborvitae is very common in areas where there is a lot of deer pressure. Many times, customers are confused about the damage being a disease or other problem other than deer eating the foliage off the bottoms where they can reach it.
Get to know what plants are magnets for the deer in your area. Ask your local ag extension office if they have a list of plants that deer prefer in your area.
Keep in mind that deer may prefer different plants in different areas. The other factor to keep in mind is that if deer do get hungry, they may eat most any plants!
The other thing to know is that any time you do introduce new plants into an area, the very first day deer may sample that new plants that you just put in place (whether the deer like it or not, they may try it to see how it tastes).
Do your homework and see what others in your area are saying about which plants deer prefer. Don’t take a chance on letting deer damage your new plants. Buy some inexpensive deer repellent and spray your new plants the day you install them just to be sure.
Remember too that in the fall of the year the male deer (bucks) may rub their antlers on the trunks of trees so it is always a promising idea to protect the trunks of young trees so they do not harm the bark. White or lighter colored trunk protection is best to reflect the heat in winter.
Trees that you may want to try on your property might need to be fenced until they get large enough that the deer can’t reach the bottom branches.
Remember that deer repellents do work, but the rain and weather will wash off the effectiveness and must be re-applied occasionally. A little persistence with the repellents is worth the preservation of the plants in your landscape.