Japanese Maple tree with wet rot at the center - Ask Extension
I have a Japanese Maple tree that is about 25years old. As it has grown, the three trunks sprout in different directions, and in between the trunks th...
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Japanese Maple tree with wet rot at the center #942176
Asked August 11, 2026, 4:24 PM EDT
I have a Japanese Maple tree that is about 25years old. As it has grown, the three trunks sprout in different directions, and in between the trunks there is a depressed "bowl" area that is approx 5inches deep. Water is collecting in this area, and we found slugs and some rot developing in this depressed area. We got rid of the slugs, dried out the area, and put a cotton rope cord to help syphon out water. But a few days after I did this, again it was wet and had several slugs again in the area. How can I save my favorite tree and keep the rot from spreading? And if I need to treat the rot, how do I do that? The tree otherwise looks healthy to me.
Calvert County Maryland
Expert Response
Hi,
The good news is that your tree is 25 years old and it hasn't caused damage thus far! You mention it looks healthy otherwise, and it likely has been collecting water for some time.
Slugs won't harm the tree, and there isn't a product or method to "stop" or "cure" rot. That rot may not be affecting the overall health of the tree, either.
We would recommend consulting with an arborist to see if they have a solution or at least a way to cover the area so it doesn't collect water. The link provided will allow you to search for one around your ZIP code. To potentially avoid a high fee, ask if they are consulting arborists, and you can get different quotes as well.
Emily
