Q.Carissa Natal Plum disease?
Hi, we’ve had a beautiful hedge of Natal Plum bushes for almost 30 years and are sadly loosing it slowly to what seems like disease on the bark. The infected bark looks like wart-like bumps on it.
It seems to be contagious as it started in one clump and is gradually moving up the hedge to all the remaining bushes. Parts of the infected bush are thriving and blooming so it’s confusing as to how we should address it. Unfortunately it’s not going away, just affecting more bushes!
Thanks for listening!
Deb
This looks like Black Knot disease.
This article has more information.
https://www.gardeningknowhow.com/edible/fruits/plum/black-knot-tree-disease.htm