Fungus growing on Coral Bark Maple - Ask Extension
Hello,
I have a fungus growing on a coral bark maple. I have had the maple for 2 years. In was in a pot for about a year and in the ground for less...
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Fungus growing on Coral Bark Maple #923034
Asked December 22, 2025, 1:16 PM EST
Hello,
I have a fungus growing on a coral bark maple. I have had the maple for 2 years. In was in a pot for about a year and in the ground for less than a year. I transplanted it in early November. In its new spot this fungus started to show. The tree is green above the fungus.
What are the possible causes and is it salvageable? I was thinking about digging it up and pruning the roots and spraying with a hydrogen peroxide solution. If I do find root rot, should I discard the soil?
Can I dig it up now or should I wait until spring?
Thanks in advance!
Washington County Oregon
Expert Response
Hi Joshua and thanks for your question and good pictures of your poor Coral Bark Maple tree. It looks pretty bad with the bark sloughing off and the fungus looks pretty well established which means it has "roots" well into the tree.
You don't say how big the tree is, but I don't think spraying the roots will do anything. I don't see any root flare at the part of the picture I can see, so it may have been planted too deep and had trouble establishing a good root system.
I think I would pull it up and look at the roots to see if they look healthy, and then plant it again with the base flare above ground and the roots spread out as far as you can make them. The hole should be twice as big as the root area, not any deeper than it was in the pot, and not filled with any additions to the soil other than what you dug out of the hole.
If the top is still fine, the tree may be able to recover, but if the fungus has gained too good a foothold, you may want to be looking for a replacement tree.
I hope this helps,
You don't say how big the tree is, but I don't think spraying the roots will do anything. I don't see any root flare at the part of the picture I can see, so it may have been planted too deep and had trouble establishing a good root system.
I think I would pull it up and look at the roots to see if they look healthy, and then plant it again with the base flare above ground and the roots spread out as far as you can make them. The hole should be twice as big as the root area, not any deeper than it was in the pot, and not filled with any additions to the soil other than what you dug out of the hole.
If the top is still fine, the tree may be able to recover, but if the fungus has gained too good a foothold, you may want to be looking for a replacement tree.
I hope this helps,
Hello and thank you for your response. I’ll dig up the tree and raise it up more. I am not sure the total age of the tree but I have had it for 2 years.
Will the dead part of the trunk slough off over time?
I attached a photo of the current planting depth.
Hello and thank you for your response. I’ll dig up the tree and raise it up more. I am not sure the total age of the tree but I have had it for 2 years.
Will the dead part of the trunk slough off over time?
I attached a photo of the current planting depth.
Hi again Joshua and thanks for the photo confirming my guess that the tree is planted too deeply. I don't know if the tree will slough off the bark and try to repair itself. Some do. But it will depend on how much cambium layer (the growing layer) is left on the part not in the pictures. If the tree seemed normal this summer, there is hope!
Happy Holidays,
Happy Holidays,
