Every year about this time, customers start bringing in photos of this strange white, fluffy substance on the stems of their shrubs and perennials. I myself have it on the stems of my Rose of Sharon. What on earth can it be?

Well, it is not a fungus, as some have suggested. It looks fuzzy, so could it be a mealy bug? Nope. It is an evasive little insect called a leafhopper. I say evasive because if you’ve ever seen one on a stem, as soon as you get close they quickly shift to the other side of the stem to hide. This particular type of leafhopper secretes waxy filaments to disguise itself and protect itself from predators. That is the white “fluffy” substance you are seeing.

There are many different species of leafhoppers and plant hoppers. Leafhoppers have sucking mouthparts and suck the plant cell contents from stems and undersides of leaves. Some of them spread plant diseases. If you have just a few of these pests, blast them with a water hose when you are out watering. After a few days of blasting, their numbers will be reduced. If your plant is infested, it may require spraying with a product that is listed for leafhoppers. Please consult Backbone staff for recommendations.