Arborvitea turning brown

Asked May 26, 2020, 2:36 PM EDT

I have a row of 3 arborvitae planted about 5 years ago and now about 5 ft wide by 15 feet high each. One of the plants is turning brown on the inside and backside. What do I need to do? How can I stop the spread if this is a disease?

Richmond Virginia

3 Responses

Thank you for your question and pictures.

Arborvitae are very problem-free in terms of diseases. We have been seeing problems with the plants over the last couple of years having their root system affected by the excessive rains in 2018-19 but the pictures you submitted don't show the same symptoms we saw with that.

Arborvitae are not shade tolerant plants. That is why they will thin out on the inside. These plants are growing along a fence. And it looks like the area that is browning is at the base of the back. It is most likely that they have gotten big enough that the plants and the fence are providing too much shade to the lower back portion of the plants.

Regards,
Ed

Horticulturist at Southern States suggested it was an air flow problem because of the fence. Somewhat frustrating since I paid Sneed's landscaper to plan and plant that area. Landscaper told me the plants were where they needed to be in relationship to the fence with 5 foot centers to allow for growth. Right now it is only affecting the smallest one on the far left. I have cut out all the brown branches which will improve air flow. But I will not be taking down my fence. Will shade provided by the fence eventually kill my arborvitaes?


No the shade from the fence will not kill the arboritaes. The backside below the fence line will loose its foliage. But from the top of the fence up and on the open yard side, there won't be any loss due to low light. And you won't notice the bare back.

Ed