Knowledgebase
Aarborvitae tree #868854
Asked May 17, 2024, 11:02 AM EDT
Chittenden County Vermont
Expert Response
Hi Janice,
I'm sorry that this has happened to your arborvitae trees. At first glance this looks like winter injury, but considering that these trees have been in place for 19 years and are just now showing the browning there must be something else going on. With all of the rain and flooding last year, were the trees ever sitting in standing water or do you have heavy clay soil? With the cycles that we have had in the past couple of years with the rain and droughts that could have just been too stressful for these trees.
Unfortunately at this point it appears that there is too much browned dead material for the trees to survive. We would recommend removing the trees and replacing them with something else. If it is a wet spot, and hydrangeas are doing well there you may consider adding more of those since they like that location.
I hope that this information is helpful. Thank you for reaching out to UVM Extension and feel free to reach out with any further questions.
Thank you,
The plant pathologist provided the following on the hyrdrangea issue:
The hydrangea pest is the hydrangea leaf tier. It is common this time of year on certain hydrangeas. You can handpick the affected leaves and destroy. Once the caterpillars have tied the leaves together, they are protected from insecticide sprays!
https://bygl.osu.edu/node/1568
Regarding the trees not being in clay soil and standing water:
If there is more browning on one side than another, then it's likely wind damage, winter dessication, etc. If there is any new growth, that means the roots are alive. They could try a shot of fertilizer/composter and wait and see if that helps, but at this point the trees are to far gone to save. They will never recover enough to look nice and green again. She does not believe it is any type of fungus.
