Arborvitae care

Asked June 18, 2020, 12:17 PM EDT

What causes the brown sports on my arborvitae

Clackamas County Oregon

4 Responses

Please send several pictures to help diagnosis.
1.) The tree and its surroundings.
2.) The tree, alone.
3.) A close view of the damage/brown spots.

Also, tell me the following:
1.) When the tree was planted.
2.) How often do you water it?
3.) Do you fertilize it? If yes, when and with what kind of fertilizer?
4.) What have you tried, so far, to fix the brown spots? Did it help?

I have attached a picture. It is part of a very large hedge the ground is normally very wet. We did loose two trees last year. I do not water them and have never fertilized them

The tree was planted at least 15 years ago.
It is part of a 200 foot hedge.
We do not fertilize or water it.
We have only cut the area out.
We had two trees at the end of the row that died last year.

One other question, we have can we trim the hedge this time of year?

Thank you for your help.

Thank yoo for the update.

My concern was your comment about a wet site. Seeing the row of trees can reveal stressed trees because they are off-color, a somewhat blue-green or gray-green. But, the hedge appears to be in a good condition, at least in the photo.

For the immediate term, I suggest you investigate the brown, dead area. It may be simply a cracked or broken branch that can easily be removed.

If large amount of sap is oozing, or is running down the trunk, or even if nothing remarkable is seen, consider contacting at least 3 Certified Arborists for on-site evaluations. (We suggest Certified Arborists because they must pass an exam and also must accumulate continuing education units.) Such evaluations are often free but ask while you are arranging the visit.

You can locate local Certified Arborists by searching with your zip code at Most local Certified Arborists service all 3 metro counties.