Q: Hi, I have two different varieties of arborvitae, the green giant and emerald. We had a severe drought this summer, and I watered the soil at the base of the trees about once a week. The giant (thuja) has large patches of golden brown branches, on the inside, the ends are still green. I treated it with a copper/oil solution I purchased at a local garden center. It doesn't seem to have made any difference; although, the amount of the tree that is discolored has not increased, so maybe it stopped the progress. The emerald are fairly old, and about 35' tall. I have lived in this home for 20 years, and they were here when I bought the property. These seem to be dying. The entire top of one is brown, and a lot of the inner leaves are turning brown. They have done this for many years and seem to be fine the next spring. My questions are, do you have any idea what the problems are, and is there anything I can do to save the trees and return them to a healthy state. Neighbors who have arborvitae seem to be having similar problems to a lesser degree.
Keith, There could be many reasons. I recommend you have an onsite inspection by a certified arborist in your area. In uneducated guess could cost you your trees. Best And Happy Yardening, Nancy