My Japanese Maple’s Branches are Dying

Credit: Eric E. Castro

Q: My Japanese Maple tree seems to be dying. The leaves on the right side are falling off and several branches are now dead. In the same plant bed, there are also hydrangeas, hostas and two small rose bushes. They get watered at least twice a week.

Do you have any suggestions as to how I might save my tree?

Thank you.

There are two possible problems:

One possibility is “Wilt” (Verticillium dahlia). This fungal disease enters a plant through the roots. Once inside, the fungus obstructs the vascular system and inhibits the travel of water. The symptoms are actually nutrient deficiencies – yellowing, wilting and dieback of young twigs and branches. Carefully scrapping the stem may reveal black or brown streaks beneath.

No chemical measures are available to cure wilt. Try deep watering, mulching with compost, and periodic feeding to speed up the self-healing process.

The second possibility is either fungal “Anthracnose” (Kabatiella apocrypta or Discula spp.) or “Bacterial Blight” (Pseudomonas syringae or pv. syringae). Both are common plant diseases.

The fungal anthracnose causes irregular blotches that are brown or white on the leaves and twig dieback. Overhead watering can easily spread the fungal spores. To control the spread of spores, remove dead branches and leaves. Increase air circulation around and within the tree canopy.

Bacterial blight will cause the twigs to appear more blackened than anthracnose does. The ‘Sango kaku’ and ‘Oshio beni’ are very susceptible cultivars. Control measures are the same for bacterial blight as they are for anthracnose. One method you might try is a liquid copper spray.

Ultimately, I would suggest seeking a second opinion from a certified arborist to do a visual inspection and/or lab analysis for further clarity.