I have a weeping mulberry tree and last year it got some kind of white stuff on it: can you tell me what this is and how to get rid of it?
The Gardener’s Answer
Hello, Ernestine: The common mulberry tree (Morus alba) is very susceptible to a fungal disease commonly known as powdery mildew. I suspect this is what your tree is suffering from. In most cases it is not fatal, but it should be controlled for a healthier tree. In general, plants are more likely to become diseased when they are not living in optimal conditions. If your weeping mulberry is growing in a shady location with poor drainage and/or poor air circulation, this fungi will continue to be a problem. Good sanitation practices throughout the growing season are important for reducing spores as well as from over-wintering and re-infecting the tree the following year. Make sure to remove and dispose of all dead foliage on and around the tree. You want to avoid overhead watering, there is no benefit to watering the foliage; in fact it can make the mildew worse. This fungus thrives in hot humid weather and for those of us gardening in Kentucky, it is hard to avoid these conditions. Spraying with a fungicide is an option of last resort in my opinion. Good cultural practices will be very effective in terms of keeping the fungi under control. Some plants are more likely to become infected with powdery mildew than others, and mulberries are very susceptible. It is always a good idea to plant disease-resistant cultivars.