I propagated some cuttings of red twig dogwood last summer. They were growing wonderfully until I noticed some stem canker where the stems branch off. At first it was only one or two, not its on all of them. Im worried that its a fungus that can be spread. Internet says that canker is a type of stem blight. I know red twig dogwood is susceptible to canker.

Do I need to trash these plants?

Anyone know what causes it and how to prevent it before I take more cuttings?

THANKS!!!!!!!

Trisha