Thank you for the photo- it helps us identify what is going on. From the picture this looks like Leaf Spot which is a fungal disease. There will be spots on the foliage of the shrubs and the leaves may turn yellow and drop prematurely.
You can spray/apply Fungonil RTU
To help control the disease, remove any infected leaves and dead twigs that have fallen on the ground. Remove all leaves from the ground once they have fallen this fall.
It is also important to avoid watering over the top of the plant. Always water shrubs, trees, perennials at the base, under the leaves. Extra moisture on top of the leaves makes them susceptible to fungus and disease.