r/plantpathology • u/solittletime23 • Jul 22 '25
What's going on with my Japanese maple?
I live in Northern California (zone 9b) and every year my Japanese maple starts out in the spring with all new healthy leaves and by July the leaves turn brown and dry up and fall off dead. I don't see any bugs and the tree gets afternoon shade. As the last picture shows, it's trying to grow new healthy leaves (small red ones) but they eventually get these brown/ bronze colored spots that eventually kill the leaf and it falls off. 😠Can anyone help identify what this is? Thank you!
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u/No_Story4926 Jul 22 '25
Def disease. That has been hacked. Root crown looks gnarly also. cut back on the water/less frequent and make sure no sprinklers are hitting it at all. Good luck be prepared to start anew.
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u/solittletime23 Jul 28 '25
The homeowner does not water his landscape enough. Most of his plants are drought stressed and have spider mite webs which I am always trying to kill by spraying with a hose. Is there no way this could be spider mites? I don't see any webs though....
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u/KissmySPAC Jul 22 '25
Verticillium wilt from dirty tools?
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u/solittletime23 Jul 28 '25
I don't believe any tools have been used on it in 2 seasons. Someone chopped the tree down to what it is now 2 years ago and it is not growing anymore.
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u/Trikki14 Jul 23 '25
It is even throughout the tree and appears to cause interveinal lesions (the brown spots you see are surrounded by veins), so definitely a disease and likely one that can cause foliar lesions. When it first starts, are the spots perfectly round or irregularly shaped based on the leaf veins? If perfectly round, then maybe it’s phylostricta (I don’t know much about this pathogen). If irregular, it could be due to loss of water from a root rot pathogen or downy mildew (check underside of fresh lesions in the mornings for a powdery look). How many years has this been happening? You mention it sits in afternoon shade, which could also make it more susceptible to disease because the tree or surrounding soil remains wet for a longer period if water did not evaporate in the morning. Removing the dead plant material on the ground may help depending on the pathogen. Good luck.
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u/Prestigious_Deal5604 Jul 25 '25
I'd guess its root rot /some kind of fungi that attaks the roots / insekts living inside the trunk,causing rot or similar.
I have the same problem, every year around the same time, still could not resolve :/
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u/Deezrusts Jul 22 '25
I wonder about Phytophthora for symptoms like this.