Some of the leaves have a black oil type film on them. It has had a superb summer with lots of flowers, but I have been noticing this for the past 2 weeks or so. What can I do please?
My Lovely Jasmin Plant
Certified GKH Gardening Expert
First it would be helpful to know if this is growing under any other trees. There are many trees that will drop sap, and cause this. There are also certain fungi that can cause this as well. Can you provide a picture, and a description of any trees or fungus nearby? This will help me to help you.