Answer: First of all, I suggest you contact the company that did the planting, and explain the situation. They may offer some type of guarantee, and may be willing to come out and check on them. I'm sure it was a considerable expense, so I wouldn't wait to contact them to see if the trees can be saved.
These are quite large trees, and the larger the tree, generally the worse the transplant shock. Heavy clay soil is challenging for any plant, so this can compound the problem. If the new growth looks healthy and green, my guess is they'll survive. If it, too, is turning brown, I'd worry that they are in trouble.
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