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!