I have 8 Thuja Giant Green trees along my property line. They were planted in March of 2014. They were doing very well. As spring arrived all the winter bronzing was gone and they were showing signs of growth. Suddenly couple of the trees have started turning brown. One of them is completely brown and other have some patches of brown. All the leaves on that one tree have slowly turned brown. I had fertilized all of the trees with the evergreen fertilizer spikes at the beginning of the spring. I do not see any signs of worms, spider webs etc. Please help!

Arborvitae having been planted in March of 2014 are not yet established with a substantial root system and while all are the same species or cultivar, their root system development can be quite different. Check for adequate soil moisture immediately next to the trunks. Surrounding soil may contain lots of soil moisture while the root ball may be dry. Your description of the plants does point to transplant stress. Syringing the foliage can lessen the stress on the root system. Check with your local Extension Service for any problems that may be localized that I would not have knowledge of