In July, we planted 9 Arborvitaes in various sizes. We watered daily via drip lines and they looked great all along. Recently, I have noticed yellowing from the inside of the tree, and it's happening with most of them. We have had 2 days of minor frost in this area. Help!
Montmorency County Michigan
It's fall. Evergreens will shed old foliage that grows closest to the trunk. That foliage will turn either yellow or brown, depending on the kind of evergreen. From what you have said, this sounds like normal behavior.
You should be concerned if the foliage is falling off all the way to the ends of the branches. Being transplanted is stressful and a bit more foliage loss could be possible this fall.