Japanese Maple Tree
Wilting Problem

Q: I have several Japanese Maples (4) that have lost some leaves and the twigs are turning brown and I can snap them off easily.

I've also noticed the main branches are turning brown (like they are drying up). What can I do to save these trees.

Thanks,
Mala

A: Japanese maples are very prone to a disease called verticillium wilt. If you have verticillium, you may have a difficult time controlling it.

Verticillium is a soil-borne disease -- it is mainly transferred by moving soil around. It has been found that earthworms can transport the disease around by their simple movement through the soil.

Probably the main way it gets around, though, is through a common human activity -- buying plants and planting them. The soil that comes with the plants may contain verticillium, and then you install it in your yard.

I'm guessing you may have planted perennials beneath your Japanese maples, and if so, the perennials may have brought in the affliction.

One way to check for verticillium is to remove a wilting branch and strip the bark up from the cut end. If you see olive-green streaking, it is possible you have verticillium wilt.

The only sure way to know is to send a few twig samples to a plant diagnostic lab, but the streaking is an initial sign.

Any badly-symptomed tree should be removed and destroyed as soon as possible as it is unlikely it can be saved, and it poses a threat to other trees.

Trees with minor symptoms might be treatable with an injection to try to suppress the disease, but this takes a special chemical and tools. If you have some that look like they might be treatable. I recommend contacting a local arborist to inquire.