Q: What’s wrong with my blue atlas cedar? Some of the needles are turning brown and the ends of several branches appear to be dying.
A: I suspect that your tree has cedar needle blight. This fungus disease is favored by prolonged cool wet weather, neither of which we experienced this summer, but still, that is my guess due to a sprinkler or maybe just a shaded location.
As you described, needles at the end of branches turn tannish-brown, and end of branches often die. In bad cases, entire branches can die, and in the worst cases, entire trees can be killed.
Although there aren’t any chemicals registered to prevent cedar needle blight, there are steps you can take to help combat the disease. Start by making sure an irrigation system isn’t wetting the foliage every time you water. If the foliage remains dry, the disease won’t spread, but it will spread all summer if water hits the branches regularly.
As soon as possible, prune off any dead branches and rake up fallen needles. The disease overwinters on dead branches and needles, so removing them from your garden will help reduce the severity of reoccurrence next spring.