Evergreens like arborvitae, yews and boxwoods can really take a beating during the winter months and suffer from winter burn. Winter burn causes sections or in severe cases, most of the plant to turn brown and die. Damage can be seen especially if the west and south sides of the plants are exposed to wind and sun. Save yourself the hassle of replacing badly damaged plants or waiting for new growth to fill the holes by taking these extra precautions.
Satisfy Thirsty Plants
Watering until the ground freezes is one of the easiest things you can do. It has been cold already,but you may find that mulch has prevented the ground below from freezing yet so give a deep soak to sensitive plants or newly planted ones.
Give them a Blanket
You can do this one of two ways, but both are not needed. One option is to use Bonide Wilt Stop on sensitive plants. Wilt Stop is a natural, non-toxic spray made from the resin of pine trees that creates a film on the needles or leaves to prevent drying out and winter burn.
You can also create a burlap screen around the plants to keep them shaded from the winter sun and cold winds too. Sometimes this can prevent deer from nibbling too, but they have been known to just rip the burlap off to get at the foliage. Ideally you want to place stakes around the plant and attach the burlap to the stakes, but wrapping the plant works in a pinch too.