Question
I recently purchased and planted 3 hydrangea.  I have noticed that there are purple spots on the leaves.  They seem to be increasing rapidly on one of them.  There is also some white powdery substance on them.  The leaves do not seem to be dying or wilting.  From what I have researched, it seems to be some type of mildew.  However, I am unsure as I know close to nothing regarding plant diseases.  I would like to know what I can do to cure the problem so that my hyrdrangea will be healthy. I live in Cleveland, OH.  Thank you, Allison Golem

Answer
Hi Allison;

It is called powdery mildew, a fungus disease. You can control it very easily with most fungicides available at a garden centre. Just follow the label directions and make sure the product is effective against powdery mildew. The disease  overwinters on the fallen leaves, so make sure you get rid of the leaves that fall and put them in the garbage. You can lessen your chance of getting powdery mildew by making sure the plants get lots of sun, the leaves stay dry especially at night and there is good air circulation around the plant. Hope this helps.  JOHN