I am at a loss to understand why two out of 12 new, 6-7 foot American emerald green arborvitae just decided to suddenly give up the ghost. At first, I had noticed a somewhat wide (8-10”) symmetrical, brown strip, down the front side of each shrub, from ground to top. The rest of both was still somewhat green! 10 of the 12 shrubs, are across the yard, and doing beautifully, all were planted almost 2 years ago. These two were fine, until mid to late Sept., when this brown stripe appeared. No matter what I had done, it became progressively worse for within about 4–6 weeks. With an extremely hot and very dry summer, I had thought that watering those two and 10 other larger arborvitaes, on either side of the sick ones, would help. All other shrubs are doing extremely well, except for these two. 1-2 weeks after watering, sufficiently, they became worse. Also, I had fertilized those with a safe, liquid fertilizer water. Nothing helped. Shortly before I had started research as to the cause, I decided to tamp down the dirt around their bases, with my foot. Strangely enough, a 10 to 12 inch ring around the base of each shrub, my foot sank down in, about 4-5 inches!!! I’m fighting a very aggressive mole problem, but they eat grubs. Gophers, or something like those, do eat roots. Question: If gophers or the equivalent, why in the world target only these two shrubs, and not touch the other shrubs on either side of those two?! In total, my entire backyard is bordered by about 45-50 well established, lush arborvitaes. Could there have been a ridiculously large number of grubs, around the roots of these two shrubs, and with my ravenous, horde of moles, could they have caused so much air to be around the roots. Therefore, drying the roots, which I’m sure most were just starting to grow out into the soil, from the potting soil which was the shape of their planting pots, killing the shrubs? A fact is, something caused that dirt around both of those shrubs to “fluff“ up. Then, to sink down, when I tamped/stomped the dirt down around their bases. I have no clue as to why I had done that, which has ended up being my best clue. At present, they do have some hint of a sickly looking yellowish-green within all of the brown. Not 100% brown, yet, but darned near close to it.  I’m buying stock in the “Grubex” company! My main hobby is gardening. I’m just sick about it, because those shrubs, on sale, were $50 each. ...enough to make a grown man weep. (It would have to be too dark for a helpful photo!)