Evergreen Tree Browning

Asked June 17, 2019, 2:50 PM EDT

This tree developed a spot about six weeks ago, which began as an area where the foliage began to loose it's color and become limp before then turning brown. Initially there was only one of these spots, but now two more have developed, one further up the tree above the first spot, and another beside the first spot. The spots are approximately 12"x12". I have three more of the same type of tree planted close by. Is there something that I can do to correct the problem on the infected tree? And, is there anything that I can do to protect the other three trees? Thank you.

Baltimore County Maryland

1 Response

This arborvitae looks like it is suffering from some sort of root or trunk damage. From the photo, it is hard to say what could be the cause. Root damage occurs for various reasons like wet, soggy soil, soil compaction which causes poor root growth, and occurs on trees that are planted too deeply with too much mulch around them. Another root issue cause can go back to when the tree was planted. If the tree was planted with the root ball wrapped in burlap or the root cage was not removed as the tree grows larger it constricts the root system causing problems. Once the decline begins it usually is not possible to stop the progress.

A long shot but worth mentioning is a pest called Japanese cedar longhorned beetle. Look along the stems for exit holes and tunneling. Refer to the following information from our website,
https://extension.umd.edu/hgic/topics/japanese-cedar-longhorned-beetle
Pruning out the damaged stems is the only control.

Deb