My Arborvitae’s Outer Branches Are Turning Yellow/brown. Is It Due To Drought? Fungus? Anything Else?

Question

I planted 15 arborvitae Thuja Occidental in October of 2020. They did great through Fall and the Winter Season. Since Early March, I have noticed that some parts of the outer trees are turning yellow/brown. I fertilized them Early April. It has been a very try spring so far in Boston but I have watered them regularly (not sure if enough). Please see attached photos. What is the root cause of this problem? is it drought, fungus, or anything else? Should I prune the tree?

Answer 1

Unfortunately, your photos did not come through. I am unable to see the damage. They are very sensitive to overwatering, and that is usually what will cause browning. Make sure that the soil has plenty of time to dry out down to about 2 or 3 inches or so between watering. Water deep in between these mild dry outs.

Here is an article that will help:

https://www.gardeningknowhow.com/ornamental/trees/arborvitae/growing-arborvitae-trees.htm

From here, a fungicide may be necessary. Here is an article that will help you with fungicide use:

https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm