Tales from the Help Desk, Mysterious Spots

Q. What is going on with my weeping redbud? Most of the leaves are covered in spots and many have black areas. 

A. The spots and blackening areas on your weeping redbud appear to be fungal infections that probably include anthracnose. It is not unusual to see redbud trees (and almost any deciduous tree) in the fall with fungal infections showing up as spots and blackened areas on the leaves. This seems to be especially common on redbud trees. The health of the tree is not seriously endangered. 

The best thing to do is to clean up (collect and destroy) all infected leaves as they fall from the tree. Do not put these in a compost pile but bag them and dispose. Prune out any dead branches. When the tree is dormant (late January to early March), you may want to prune selectively to promote air circulation. In the spring apply fresh mulch. 

You may want to spray the redbud with a fungicide when the leaves are beginning to enlarge from buds in the spring. VCE guidelines for fungicides are provided in Table 4.1 of the Pest Management Guide: Home Grounds & Animals. 

The fungicide is a preventative aid and should be applied just before the leaves fully come out on the tree. It will not kill fungus already active in a plant. Applying a fungicide to the redbud after the leaf spots appear would serve no purpose.