There is a powdery substance on the bottom leaves of our Ninebark bush. Can you suggest anything I could make or buy or make to solve this problem?
Hello, I am sorry to say that you have powdery mildew on your Ninebark Physocarpus . The weather we are encountering now is perfect for fungus of all kinds and especially for powdery mildew. Many species of Ninebark fall prey to this disease, and to my disappointment I found evidence of the same just yesterday on my own Ninebark. However, by the look of your photo, it seems that you have caught this early and so the outcome for your plant is good. Here is a link to a Master Gardener’s reply to a similar question. The advice is sound, and as the mildew appears on the bottom on both your and my ninebark, I am sure that the incorrect watering is a big part of the problem. I am sure you will find this most informative. Good luck!