I have 4 very large arborvitae in my yard. This summer, I noticed that one of them was browning. I called an arborist who said it was dying, possibly from being too close to the others. He found no signs of disease or insects. I also consulted with the village arborist (who was here about another tree on the village right-of-way) who said the same. I had it removed. Now, I notice that the rest of the arborvitae are starting to brown. These trees form the border along my side yard, provide needed privacy and house abundant bird life. The only thing I noticed that was out of the ordinary when the tree was removed was a huge yellow jacket or hornet nest in the base of the trunk. Are all the arborvitae goners? Is there anything I can do and why, after all these years did this happen?

There have been many evergreens in decline this past summer. The cause can go back to the drought of 2012 and harsh winter of 2013. When plants are planted closely together forming a tight screen, their lifespan is potentially shortened. As you have noticed a similar decline on all of them does suggest environment, rather than a pathogen. Make sure the remaining Arbs get well watered just before you put the garden hose away for the winter and plan on feeding them next spring to assist in recovery.