What is causing my arborvitae to turn brown?

Asked June 22, 2015, 12:16 PM EDT

We've had these nice twin trees in front of our house entrance for past five years. This spring they suddenly started turning from all green to having massive patches of brown, as if they're dying. Any help identifying what these trees are and any way to treat the issue?

Hennepin County Minnesota

3 Responses

Your Arborvitae have suffered winter damage it looks like. Unfortunately there isn't much you can do to correct the problem. By the time you prune out the damage your shrubs will not look very attractive. I suggest that you consider removing them and replacing them with something else. Visit a local nursery and see what options they have available. Remember to let them know what direction your entry faces and keep in mind that many evergreens need regular pruning. There are many choices in evergreen and deciduous shrubs as well as attractive containers that you could plant.

It does not seem like a winter damage because (1) the winter was very mild, and (2) in early spring these trees very all green. So, what else could be the cause, like fungus, etc? Can we try using some chemical spray before choosing to remove them? Really don't feel like removing them.

Winter injury often doesn't show up until now. Here is a link that explains what happens. http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/winter-injury-on-trees/. You can do whatever you like but there is no magic spray that will bring the dead part of your shrubs back to life. You can prune out all of the dead material and shear back some of the live part and wait for new growth but it will take a long time to fill in the bigger holes and they may never fill in if the damage is really severe. Here is a link to some info on pruning evergreens. https://extension.unh.edu/resources/files/Resource000594_Rep616.pdf