I have a six-year-old viburnum; 10 ft tall; 14 ft wide. Produces an abundance of flowers but not many fruit due to almost total loss of honey bees in my area (Baltimore City 21218). Last week, suddenly, overnight, so many leaves dropped, the yard looks like green snow. It is still pushing out new growth at the tips but new stems from the ground have the same appearance as the dropped leaves -- mottled green shades with gray spots; appears to be on top surface of leaves. I checked my neighbors' maple, cherry, and dogwood and they are untouched. So, do you have any info to offer. Has anyone else experienced something like this? I am puzzled and troubled that I may lose it after increasingly vigorous growth each year since planting. Thank you.
We can't say for sure from your description what is afflicting your viburnum. Those are unusual symptoms. Could be botryosphaeria, a disease which is associated with overly wet soil conditions. Soils can become too wet for plant roots when soil grade changes, down spouts shift, or simply drenching rains that don't drain well. Look at some images on Google. There is no cure. If you can improve the soil condition, the plant may be able to improve and grow acceptably for years.
Diseases that affect other plant species rarely would affect viburnums.
If botryosphaeria does not seem to be the problem, we'd recommend that you send us some photos of the symptoms so that our plant pathologist and entomologist can look at them.