Arborvitae turning brown and dying

Asked June 2, 2018, 12:56 PM EDT

Arborvitae’s turning brown and dying. I have a roll of 10 arborvitae plans and five of them have died over the last 4 to 5 years. The remaining plants are all about 10 foot tall and look very healthy except one. One of these existing plants is starting to turn brown and I am concerned that the rest will follow suit. Is there a common symptom that causes arborvitae’s to turn brown in Oregon? I live relatively close to the Columbia River in hood river. Please advise.

Hood River County Oregon

1 Response

Hi and thanks for your question to Ask an Expert.

Arborvitae in the Gorge often die because of drought stress or overwatering, which causes root rot. My question would be to ask if your arborvitae is hooked up to an irrigation system. If not, it could be drought stress which is slowly killing your plants during these last few dry summers. If you do have it hooked up to irrigation, how much irrigation does the hedge get during the summer months?

Without seeing a sample, however, I am not able to rule out insects. You can bring in a sample to the Hood River County Extension office Monday-Thursday from 8am-noon and 1-5pm. Master Gardeners are in the office on Monday afternoons and all day on Thursday (minus the lunch hour).

You can find two links below that will tell you more information on drought stress and arborvitae root rot.

Effects of drought continue in Valley: although this link is related to plants in the Willamette Valley, it does relate to drought stressed conifers.

Root Rot in Arborvitae