Abor Vitae is dying? - Ask Extension
We have an abor vitae (at least we think it is an abor vitae) that is turning brown. There is a large stem that looks like it shoots off from the bo...
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Abor Vitae is dying? #801749
Asked July 18, 2022, 10:46 AM EDT
We have an abor vitae (at least we think it is an abor vitae) that is turning brown. There is a large stem that looks like it shoots off from the bottom of the main trunk that seems to be dying. This tree has been healthy since we planted it 4 years ago but suddenly this one branch turn brown and I trimmed the brown off and within two weeks the entire branch turned brown. If I cut this branch to the bottom it would leave a large hole (which wouldn't look good at all as this inside in mostly brown as there are dead needles piling up on the interior branches. Can this be saved or should we just remove it?
Orange County Vermont
Expert Response
Here is another photo to show you the area on the Abor Vitae.
Hi, Donna,
You do have a columnar form of arborvitae here, also known as cedar. The dieback of an entire branch may be caused by a number of circumstances, including an old injury, damage from insects or another pathogen, drifting herbicides, and under or over watering. It appears the shrub may get some snowload over the winter, and falling snow can cause damage if the tree is not additionally supported. Snowload can also compact the soil, causing issues of root damage or related to water uptake. Check out this article from U of Minnesota Extension on winter protection for your landscape. If snow damage may be to blame, use this simple method: in late October or November, take a piece of twine and tie at the base of the trunk then gently but firmly spiral upwards to bring the branches together and tie off at the top. Just be sure to not break any branches -- there should be room for natural movement so the tree can still "move" as conditions change through the season. Remove in Spring!
You mention dead needles on the inside of the foliage -- if they are piled in the crooks of branches, they can cause rot from build up of moisture on the bark, leading to eventual dieback or other infections or infestations of insect pathogens. Luckily, there is an easy solution you can begin to do as part of Spring clean-up (or mid-Summer for this year :) :
If you did not spot any physical injury, take a look at this page from Penn State on common arb diseases and management strategies. If you know that herbicides were used nearby, this may also be the result of herbicide injury, though with that amount of dieback, it would probably have been well over a month ago.
It is hard to see in the photo, but some of the tips of the branch still appeared green, which would lead me to believe it is trying to grow back. To double check if a branch is still alive and not just gradually dying, scratch the bark with your nail and see if it is bright green beneath. If brown or looks dessicated and grayish-green, begin pruning back, from tip to healthy growth.
If you prune, disinfect your pruners or saws in between cuts with 70% or stronger alcohol in a spray bottle. Also make sure your pruners are nice and sharp to prevent further injury to the tree.
Even evergreens will fill in over a season or two. I would encourage you to keep this one, as it is already established. Once you remove the branch, you can gently prune the entire shrub to balance out the growth. You may want to pay extra attention to how much rain you are getting, too. If you go two weeks without rain, I would encourage you offer additional water -- once per week, two 5-gallon buckets, or a 15 minute medium-slow trickle from a hose (slow enough to soak in and not pool / fast enough to cover the root ball zone and soak deeply). This will support the tree's health while it pushes some new growth. You could offer just a little extra fertilizer now, but not after August 1 (you don't want to encourage a lot of extra growth before winter). If you do, I suggest a gentle 5-4-3 organic pelletized fertilizer scratched in the surface of the soil around the drip edge of the plant.
I hope this helps!
Cheers!
Genica
You do have a columnar form of arborvitae here, also known as cedar. The dieback of an entire branch may be caused by a number of circumstances, including an old injury, damage from insects or another pathogen, drifting herbicides, and under or over watering. It appears the shrub may get some snowload over the winter, and falling snow can cause damage if the tree is not additionally supported. Snowload can also compact the soil, causing issues of root damage or related to water uptake. Check out this article from U of Minnesota Extension on winter protection for your landscape. If snow damage may be to blame, use this simple method: in late October or November, take a piece of twine and tie at the base of the trunk then gently but firmly spiral upwards to bring the branches together and tie off at the top. Just be sure to not break any branches -- there should be room for natural movement so the tree can still "move" as conditions change through the season. Remove in Spring!
You mention dead needles on the inside of the foliage -- if they are piled in the crooks of branches, they can cause rot from build up of moisture on the bark, leading to eventual dieback or other infections or infestations of insect pathogens. Luckily, there is an easy solution you can begin to do as part of Spring clean-up (or mid-Summer for this year :) :
- First, put on a long-sleeve shirt and some leather gloves
to protect your skin. - Taking one hand, gently grab the shrub/tree and shake the branches, while your other hand reaches inside the tree and helps move the dead needles down through the canopy to the ground.
- Sweep out needles from branch crotches and pull them away from the base of the plant.
- Prune out any dead wood from inside the canopy.
If you did not spot any physical injury, take a look at this page from Penn State on common arb diseases and management strategies. If you know that herbicides were used nearby, this may also be the result of herbicide injury, though with that amount of dieback, it would probably have been well over a month ago.
It is hard to see in the photo, but some of the tips of the branch still appeared green, which would lead me to believe it is trying to grow back. To double check if a branch is still alive and not just gradually dying, scratch the bark with your nail and see if it is bright green beneath. If brown or looks dessicated and grayish-green, begin pruning back, from tip to healthy growth.
If you prune, disinfect your pruners or saws in between cuts with 70% or stronger alcohol in a spray bottle. Also make sure your pruners are nice and sharp to prevent further injury to the tree.
Even evergreens will fill in over a season or two. I would encourage you to keep this one, as it is already established. Once you remove the branch, you can gently prune the entire shrub to balance out the growth. You may want to pay extra attention to how much rain you are getting, too. If you go two weeks without rain, I would encourage you offer additional water -- once per week, two 5-gallon buckets, or a 15 minute medium-slow trickle from a hose (slow enough to soak in and not pool / fast enough to cover the root ball zone and soak deeply). This will support the tree's health while it pushes some new growth. You could offer just a little extra fertilizer now, but not after August 1 (you don't want to encourage a lot of extra growth before winter). If you do, I suggest a gentle 5-4-3 organic pelletized fertilizer scratched in the surface of the soil around the drip edge of the plant.
I hope this helps!
Cheers!
Genica
