arborvitae turning brown

Asked October 6, 2019, 1:10 PM EDT

tw0 questions.
1. We have 18 yr old arborvitae in a bunch together and the tops of 3 of them are turning brown. Anything we can do to keep them/ Would cutting off tops help?

2. Planted 4 new arborvitaes this spring. water was no problem in June but things dried up in July. We watered several times a week but 3 turned all brown but leaves are not dry. One turned brown on one side.
Will they come back or should we replant some.

Wood County Ohio

1 Response

Hi. 1. No, I definitely would not cut the tops off until you have determined what the issue is. Are the tops completely brown, as if dead, or are they simply bronzing with some green tissue left? Considering that you are dealing with long-established trees and that the patterns seems to be the same in three of them, I suspect you are dealing with an environmental issue. That could be drought, either to the tree itself or just to that section due to exposure to sun and/or wind (leaf scorch). However, it could be a disease or pest, the latter probably more likely given your description. For example, bagworms are a common pest of arborvitae and can result in defoliation and browning. Ohio State U. has an excellent fact sheet on bagworms here. If you provide some photos, both close-up and far away, it might be possible to narrow down the problem. This page from the U. of Minnesota gives some other examples of issues that can cause leaf browning in arborvitae. In any case, you shouldn’t cut anything out unless you know for certain it is diseased or dead. If you aren’t certain whether it is dead, I would wait until spring to see if there is new growth or not. 2. Brown is always a bad sign for an evergreen. It sounds like the completely brown trees are dead and the one that is half brown may no longer have much landscape value. If you wanted to know for certain, you could wait to see if they produce new growth in the spring, but I suspect the odds are low.