Plum Tree Black Knots *


Dear there,

I am writing this for my mother-in-law. Three plum trees in our backyard are having severe black knots. Can we get help from you? or Can we get an expert to treat the trees? We would like to pay for any price. Please help!


Black knot is a fungal infection (Angiosporina morbosa) that affects mainly plum and cherry trees but also other trees of the Prunus genus such as apricot. The disease isn’t new. It was described in Pennsylvania almost 200 years ago.

Other inquiries to ASK regarding Black Knot and its control can be accessed through the following:

Toronto Master Gardener Cherry Tree Black Knot

Unfortunately, Toronto Master Gardeners doesn’t provide gardening services. We suggest you contact Landscape Ontario’s to find a certified professional arborist to help you with a tree problem, visit the Ontario branch of the International Society of Arboriculture here.

If your mother-in-law is a senior, and lives in the GTA, she may be able to get help from one of these non-profit organizations.

Hopefully this information will help you care for these plum trees.