A few years ago, I pulled out some Red Cedars on the West side of my house, because they were causing problems with Cedar Apple Rust. In their place, I planted two young Emerald Green Arborvitae. After one year, one of them needed to be replaced. The following year, the other original tree need replacement. Now, this year the older of the two again looks like it is going. These trees were bought at a reputable nursery in my Chicago area, and I had to pay 50% of cost for each replacement. There were no signs of insect damage. The trees were planted properly and are cared for regularly with proper watering and fertilizing. What I did observe when buying them that therewas that there was some die-back inside the tree, near the trunk. The nursery said this was normal for these trees. Also, these trees are rated for partial to full sun, so a half day's sun they receive should be enough. I'm wondering if the nursery is just selling bad stock, although this problem has been going on for several years, and they have had time to switch suppliers. Right now, the trees are growing for a year, or so, and then dying. The nursery is coming out in a few days to inspect the trees, but they will probably find some excuse to claim it was my fault the trees died. I have heard horror stories of nurseries knowingly selling defective stock and not caring for the consequences. I don't suspect a soil problem, since the Red Cedars had grown there for many years, and I have yews and apple trees nearby who are doing ok.
Sherwin D.