Arbor Vitae health - Ask Extension
Hi, we have a group of very large, mature globe arbor vitae's in our back yard. One has a distictly lighter green shade and has brown-ish areas. We a...
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Arbor Vitae health #942395
Asked August 14, 2026, 9:55 AM EDT
Hi, we have a group of very large, mature globe arbor vitae's in our back yard. One has a distictly lighter green shade and has brown-ish areas. We are worried abou losing this tree. Is there anything we can do to support its health? I have attached a photo -- the less healthy tree is on the right. Thanks!
Hennepin County Minnesota
Expert Response
Thank you for writing.
I have no idea what size these plants were when they were planted but at this time, they are packed too close together. This alone results in browning of needles and death of branches. It allows diseases to spread from one plant to the other. Poor circulation traps moisture leading to diseases that start on wet or rotted plant material.
In addition, one plant will shade the other causing needle drop. The plants will compete for nutrients and water.
And, as you can see, the plants shapes are modified by crowding.
The phots are too far back to allow me to magnify the needles but my general impression is pestalotiopsis tip blight, a condition caused by overcrowding. https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/insects-pests-and-problems/diseases/needlecasts/pestalotiopsis-tip I am concerned that this is also occuring higher up on the tree to the left (on the photo).
Although I might give a stronger opinion with a close up photo, the extent of disease on the right and the possibility of disease on the left lead me to recommend that you contact an arborist (see my signature line) to evaluate this situation and see if the right plant should be removed to try to save the one on the left.
Also, the arborvitae at far right (off the picture) appears to have needle browning as well, suggesting that there is an infectious blight that is spreading tree to tree.
I would very much appreciate hearing what an arborist says and recommends.
I have no idea what size these plants were when they were planted but at this time, they are packed too close together. This alone results in browning of needles and death of branches. It allows diseases to spread from one plant to the other. Poor circulation traps moisture leading to diseases that start on wet or rotted plant material.
In addition, one plant will shade the other causing needle drop. The plants will compete for nutrients and water.
And, as you can see, the plants shapes are modified by crowding.
The phots are too far back to allow me to magnify the needles but my general impression is pestalotiopsis tip blight, a condition caused by overcrowding. https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/insects-pests-and-problems/diseases/needlecasts/pestalotiopsis-tip I am concerned that this is also occuring higher up on the tree to the left (on the photo).
Although I might give a stronger opinion with a close up photo, the extent of disease on the right and the possibility of disease on the left lead me to recommend that you contact an arborist (see my signature line) to evaluate this situation and see if the right plant should be removed to try to save the one on the left.
Also, the arborvitae at far right (off the picture) appears to have needle browning as well, suggesting that there is an infectious blight that is spreading tree to tree.
I would very much appreciate hearing what an arborist says and recommends.
