My purple leaf plum is infected with perennial canker

Sadly, one of the trees in my yard appears to be diseased. I noticed some dead branches last fall in the purple leaf plum and made a mental note to look more closely in the spring when the garden beneath it wouldn't be so overgrown. In spite of the disease, the tree's flowers this spring were lovely.

The purple leaf plum is in the backyard garden space that I've enjoyed from the kitchen window. The pink blooms were very pretty and nicely offset by the new purple leaves.

The tree is approximately 18' tall and it dominates the west corner of the garden in the backyard. The sparse grass and moss in it's shadow hint at this tree's age. Judy and Bob, the previous owners of my garden, must have planted it long ago. I know it provided them with many moments gazing through the kitchen window at the cloud of pink and burgundy it gives us in the spring. I'm thankful for this one spring's worth.

A few weeks ago I cleaned out some of the dead branches thinking the extra air circulation would benefit the tree. It was then that I got a close look at the strange swollen areas on the small branches and huge gashes in the bark on the large branches and trunk.

I did a search on the web for diseases common to plum trees and found two could cause this. At first I thought it was a fungal disease called black knot. But, black knot was described as having swollen fruiting bodies that grow about this time of year, and I saw no evidence of those. The other possibility is perennial canker. That's what I think this is.


Perennial canker forms dark sunken cankers along the limbs and subsequent cycles of healing scar tissue and expansion of the fungus cause the infected tissue to crack, dry out and blacken. Over time the infected branches become girdled, lose vigor, and die. Given the amount of blackened cracking bark I see throughout the tree, I don't hold out much hope that this tree has long to live.

My plan right now is to severely cut back and clean out the most infected parts. As I said, I think there's little hope that will save it. But, if I can enjoy another spring gazing at this pretty tree out the kitchen window, I'll count myself lucky - again.