2 boxwoods, do not recall the variety, bought at the same time, potted in identical pots with the same soil mix. They appeared to thrive on neglect for the most part. We had these at a house we were renting, and they moved with us a couple months ago. They have been no more than 8' apart for about as long as we've had them. Whatever we've done to one has been done to the other at the same time. Currently, they're on our deck behind the house, which is shaded for the most part. They are located next to the house, just under the eaves. And, like before, they're watered when everything else gets watered. The biggest difference in the two places has been the previous place would get direct overhead sun for a few hours; at this location, a little less overhead sun.

All of a sudden in the last couple weeks, one of them has begun to yellow on the ends of the branches. The leaves are soft, and aren't falling off, but are yellow. The other plant - less than 10 feet away - appears to be doing well. Pictures are of each plant.

Any ideas as to what's wrong & how to treat it? We are located in North Carolina, zone 7B, both previous & current location.