What’s wrong with our Pin Oak and how can we help it? - Ask Extension
Please see attached photos. Our 5 year old Pin Oak had some branches that budded out but did not leaf out. We plan to trim these branches in Nov, if t...
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What’s wrong with our Pin Oak and how can we help it? #810915
Asked September 15, 2022, 12:01 PM EDT
Please see attached photos. Our 5 year old Pin Oak had some branches that budded out but did not leaf out. We plan to trim these branches in Nov, if that is your recommendation. What is the cause? And remedy? Now losing leaves on lower leaves and has spots(eggs) on leaves. Really need help. Thank yoi
Anoka County Minnesota
Expert Response
The spots on the leaves appear to be galls cause by cynipid wasps. They are harmless to the tree. See: https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/oak/leavesbumps.html
There are quite a few causes of branch die back. Trees under stress like this year’s drought and hot summer are more susceptible to disease. The most serious is Twolined chestnut borer. This is fairly easy to identify because it leaves “s” like trails under the bark. See: https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/oak/branchesdead.html
If you think the above information is not what is going on with your tree or you need treatment for Twolined Chestnut borer, an onsite inspection by an arborist can help confirm the cause of branch dieback from the choices listed in the website above. See: https://extension.umn.edu/planting-and-growing-guides/how-hire-tree-care-professional
It is okay to trim dead branches now. Avoid trimming from April through July to prevent oak wilt. See: https://extension.umn.edu/plant-diseases/oak-wilt-minnesota
There are quite a few causes of branch die back. Trees under stress like this year’s drought and hot summer are more susceptible to disease. The most serious is Twolined chestnut borer. This is fairly easy to identify because it leaves “s” like trails under the bark. See: https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/oak/branchesdead.html
If you think the above information is not what is going on with your tree or you need treatment for Twolined Chestnut borer, an onsite inspection by an arborist can help confirm the cause of branch dieback from the choices listed in the website above. See: https://extension.umn.edu/planting-and-growing-guides/how-hire-tree-care-professional
It is okay to trim dead branches now. Avoid trimming from April through July to prevent oak wilt. See: https://extension.umn.edu/plant-diseases/oak-wilt-minnesota
Looked very carefully and could not find any squiggly insect trails in the tree truck. Went to trim dead branches and they snapped off in our hands. They only other thing we noticed was a splice in the tree truck bark. Photo attached. Do you have any suggestions or recommendations?
Thank you for your prompt response and great information. Judy Jung
A couple of things are evident in the tree trunk picture and they could be the cause of the problems. First the cut in the trunk. It is not possible to see how deep it is, but an arborist would measure the depth of the cut to determine the likely impact on the tree. Usually the tree can heal superficial cuts. Whether or not the cut provided entry to pests is unknown.
Secondly mulch should never touch the trunk. When it does touch the tree, it provides a place for mice and insects to hide and girdle trees. Pull back the mulch at least 6-8 inches from the trunk. There is also no root flair visible. This can mean that the tree was planted too deep and has stem girdling roots. Pull back the soil under the mulch and look for the root flair.
When trees are planted too deep they send roots up and around the tree rather than down. When this happens trees can die because water and nutrients are cut off. They also are more likely to blow over in storms. The following website has pictures that show you what to look for.
https://conservancy.umn.edu/handle/11299/226077
Secondly mulch should never touch the trunk. When it does touch the tree, it provides a place for mice and insects to hide and girdle trees. Pull back the mulch at least 6-8 inches from the trunk. There is also no root flair visible. This can mean that the tree was planted too deep and has stem girdling roots. Pull back the soil under the mulch and look for the root flair.
When trees are planted too deep they send roots up and around the tree rather than down. When this happens trees can die because water and nutrients are cut off. They also are more likely to blow over in storms. The following website has pictures that show you what to look for.
https://conservancy.umn.edu/handle/11299/226077
Thank you again for your advice and rapid response. Will pull back mulch. If the tree was planted to deep, there isn’t anything we can do. This tree has been in the ground for 5 years
Thank you again,
Judy Jung
An arborist might be able to correct circling roots if that is the problem. They prune the roots. You should be able to see the roots when you pull back the mulch and the soil.
