Are hydrangeas bothered by any diseases or insects?
While hydrangeas in landscape settings are relatively pest free, under certain growing conditions some diseases and insects can become problems. For the bigleaf hydrangea, the major disease problem is powdery mildew (see image at right). It is most common on plants growing in shade and under high humidity conditions. Powdery mildew infested leaves are covered with a light gray powdery-looking substance. Purple splotches may also appear. Powdery mildew rarely kills plants, but is unattractive. Powdery mildew may occur on other hydrangea species, but is most severe on bigleaf hydrangea. There are several fungal leaf spot organisms that attack Hydrangea. Leaves develop brown to gray lesions surrounded by purple halos (see image at left). These leaf spots are most common in late summer and early fall, and seem to be more common among plants grown in sunny locations. Again, plants are rarely killed, but severe infestation can be very unattractive. All the cultivated species of Hydrangea are
