eXtension

Western Red Cedars

Asked November 30, 2018, 9:08 AM EST

I have 14 cedars that were planted just over 2 1/2 years ago and one is suffering severely from something. The leaves on top are greenish brown however, the bottom sides are dark green. I have 3 others that have some browning about a foot to a foot and a half down from the top. This problem seems to be moving from the top down. The rest of the cedars are fine at this time. I've looked for obvious signs that I've read about but I haven't seen any. There has been no change in the area of the trees since they were planted. Is it possible to save this tree and help the other 3 trees? Also, could you tell me if these are actually Western Red Cedars or what variety?

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Multnomah County Oregon trees and shrubs urban forestry

2 Responses

These do appear to be western redcedars. As for the cause of the browning, I cannot tell for sure from the photos. Redcedars do tend to "bronze" during winter especially on leaves that are most exposed to direct sunlight. But it also looks like this might be a leaf blight. Are the browning leaves actually dying at this point? Close inspection of the leaves may reveal signs of fungal blight.

Drought stress has been a common cause of redcedar top dieback. But in your case it appears that these are landscape trees that get watered and have been growing pretty well. On the other end of the spectrum, too much water and fertilizer can also cause problems for redcedars.

To pursue further diagnosis I advise that you contact the OSU Master Gardeners. https://extension.oregonstate.edu/mg/metro/have-gardening-question
They can get more details on the history of these trees and your irrigation and fertilization practices. And if it seems warranted, they can look at samples or help you get some samples to the OSU Plant Clinic for testing.

Thank you for your response. I've discussed this with an arborist and he says the tree has spider mites. The other 3 have a similar look but only at the very top part. I understand that the mites have gone dormant for the winter however, I'd like to know your recommendations for dealing with this. As I stated before, the bottoms of the leaves are a dark green so I'm thinking I can get a handle on this and not lose my tree. Once again, all the other trees seem to be fine. I will keep in mind the OSU Master Gardeners site.
Thanks again