Hibiscus Leaves Have A Sticky Powdery Substance On Them

Question From: s. ADAMS - Regina, Saskatchewan, Canada
Q: my 3 year old hibiscus is healthy, blooming, but has a sticky, powdery layer on some of .the leaves. The substance is also appearing on the window \(southfacing) suggesting that flies/aphids of some sort are the cause, but when I shake the leaves nothing flies away. it doesn't seem to be spreading to the other plants. not sure if I should spray with a mild dish detergent or get something stronger

A: My guess is you have powdery mildew and possibly aphids. They also exude a sticky liquid. The powdery mildew is plant specific and will not spread to other plants. Hibiscus are prone to insects. If you have powdery mildew you will need to use a fungicide. A nice warm shower and a stiff stream of water will knock off aphids. I can't recommend a pesticide as I don't know what is available in Canada. I would use a Neem oil product here in the states. Best And Happy Yardening, Nancy