What is this growth on the branches of this bush?

Asked April 28, 2015, 9:55 AM EDT

We have a bush located in McCook County, South Dakota, that has some thick black growth on the branches. It is very hard and dry, looks like large animal poop strung out along the branches. Not sure of type of bush, possibly lilac. It has small white flowers.

Fall River County South Dakota

1 Response

It sounds like Black Knot disease, a fungal disease common on American plum and chokecherry (see pictures below). The "knots" you see on twigs are from last year.
You can prune them out by removing affected twigs; that is harder to do if knots are on main stems/trunks.

Prune several inches below knots, spray Lysol on pruner blades before making another cut. Collect pruned-out knots in a sealed plastic bag and discard.