Thank you for contacting the UGA Extension - Cherokee County Office and Master Gardeners concerning damage to your arborvitae.

Any number of factors can cause dead or brown foliage on evergreen plants. Stress (non-disease) culprits include extreme temperature exposure and drought or too much water. For example extreme cold temperatures like we experienced last winter can cause winter desiccation injury, also known as “winter burn”.  I have included a link that describes this condition in more detail along with considerations for treatment. Insect infestations, physical injury or exposure of the plant or sections of the plant from herbicides or harmful chemicals can lead to die-back of evergreen foliage. I have also included a general article that describes the most common causes of non-disease or stress related “die-back” in conifers, including arborvitae.

Dead branches and brown foliage can also be caused by a number of arborvitae diseases. These are primarily fungal in nature. I have included a link that outlines these diseases along with general recommendations for treatment.

From the picture you provided, it is difficult to determine specifically what is causing the condition of your arborvitae or to know what the appropriate treatment should be. Branch samples of both apparently healthy foliage and brown/dead foliage can be submitted to our office and we can then send them to the state lab for examination if necessary. The UGA Extension – Cherokee County Office is located at the address provided below. We encourage you to bring samples to the office Monday through Wednesday.

Likewise, answers to the following questions may help us in pinpointing what is going on with your arborvitae.

1. When did you first notice the problem and has it appeared to get worse since you first noticed it?

2. Has any physical damage occurred to the trunk or bark i.e. lawn mower bumping roots/trunk, bark splitting, etc.?

3. Have any weed & feed products, chemicals or herbicides been used on home or lawn areas adjacent to the plant?

4. Do you see saw dust on the bark or at the base of the trees or is there any other evidence of insect infestation?

5. Do you see any areas where sap is extruding onto the bark of the plant?

Please don’t hesitate to contact the UGA Extension - Cherokee County Office if we can be of additional service.

Ken Loud