Troubleshooting
Japanese Walnut problems — and how to fix them
Japanese Walnut (Juglans ailantifolia) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Heavy seed and string litter
Long pendent nut clusters and large leaves drop abundant litter; site away from paths and patios where husk drop and staining are a nuisance.
Walnut husk fly
Maggots feed in the thin husks, staining and degrading kernels; sanitation of fallen nuts and timed sprays manage the pest in orchards.
Large spread crowds gardens
Fast growth and a broad crown quickly shade and outgrow small plots; allow generous spacing from buildings and other plantings.
Juglone sensitivity nearby
Like other walnuts it releases juglone that can harm sensitive plants in its root zone; choose juglone-tolerant companions.
Prevent japanese walnut problems before they start
Most japanese walnut issues are care-mismatch, not bad luck. Dial in the basics:
Looking for japanese walnut in general rather than its problems? Read the full japanese walnut care guide — light, water, soil and feeding.
Japanese Walnut problems — FAQ
Why is my japanese walnut heavy seed and string litter?
Long pendent nut clusters and large leaves drop abundant litter; site away from paths and patios where husk drop and staining are a nuisance.
Why is my japanese walnut walnut husk fly?
Maggots feed in the thin husks, staining and degrading kernels; sanitation of fallen nuts and timed sprays manage the pest in orchards.
Why is my japanese walnut large spread crowds gardens?
Fast growth and a broad crown quickly shade and outgrow small plots; allow generous spacing from buildings and other plantings.
Why is my japanese walnut juglone sensitivity nearby?
Like other walnuts it releases juglone that can harm sensitive plants in its root zone; choose juglone-tolerant companions.