White cotton like substance on plant stems

Asked July 19, 2020, 6:54 PM EDT

This just showed up on a ninebark and other nearby plants we put in this spring/summer. Do we need to worry about eliminating it and if so, how? Thank you

Harford County Maryland

2 Responses

This is caused by an insect called a planthopper. The nymphs are covered by a waxy material and also leave some behind on the stems of plants. Try washing it off with a hose but most likely it will return. They are unsightly but don't cause significant problems. The following is a link to information about them from our website,


Thank you for the speedy response! I'm glad to learn it is nothing ominous.