Sick Plum Bush/Tree - Question

[FB.]

I have a Victoria Plum, grafted onto SJA rootstock.
The plum is several years old and has a height/spread of about 6ft.
It has never thrived since planting - only adding perhaps six inches per year and with one or two lower branches dying each year.
I gave it a close inspection a few days ago and found slightly sunken and slightly purple-red patches of bark all around the trunk and all the way down to the rootstock. You have to be very close to notice the sunken bark or the colour difference, which is probably why it had gone unnoticed - presumably for some time, considering how extensive the damage.
It completely encircles the base of a couple of branches that have died recently. I am presuming that it's canker.
With it's extensive sunken areas that merge completely in many places on the trunk, I can't see how on earth the tree hasn't been girdled already.

The tree has been carefully dug out today (it's spot has now been occupied by an apple). The plum is now in a large patio-type pot, pending a decision on it's fate.

Looking at the plum tree, considering that it is still alive despite the terrible trunk lesions that completely encircle it in many places, I wonder if it might get over it's problems if planted in a good position, given time and some TLC. Clearly there is still sap flow through the trunk and it seems no more ill than in any previous year. It was only the apparently cankered trunk combined with it's poor establishment that caused me to remove it.

Might it survive, since it's still "hanging in there" at the moment?
There aren't any other plum trees nearby that it might infect.
Or should I bin - it in an unsympathetic, ruthless, cold-hearted way?
Or might I have mis-diagnosed canker and it's something else?

What do you think?

Thanks,
FB

[rustylady]

I'm a sucker for adopting/rescuing plants etc that are past their best. I've had quite a lot of successes, so if you have the space and the patience, then give your plum some TLC and see how it goes. What was the root system like when you dug it up???

[Tam]

It sounds like bacterial canker, but affected trees normally produce plenty gum as well as the lesions you describe. This canker also has a really unpleasant smell.

[FB.]

It sounds like bacterial canker, but affected trees normally produce plenty gum as well as the lesions you describe. This canker also has a really unpleasant smell.

There is no gum and no smell - and never has been.
But in other respects, it's very suspicious for canker.
The plum has been failing to thrive and the whole trunk has many areas of sunken and purple-red tinted bark, but no gum. Where the sunken/discoloured patches surround the base of branches, the branches have died - as might be expected with canker.
Leaves have never been affected, nor does the sunken bark appear on the main branches.

Despite the numerous similarities to canker, could the lack of gum or smell be indicative of some other disorder?

What was the root system like when you dug it up???

the roots were disappointingly weak - hence being able to fit the whole thing into a large patio pot. the roots extended for perhaps a foot in each direction and a foot deep.
The roots didn't appear diseased.

FB

[FB.]

Well, I have given the plum a second chance and re-planted it in another place, where poor growth won't be a problem. The new spot is shaded at ground level, so is a little damper than it's previous spot (but the new spot does not waterlog).
Perhaps that will be beneficial to it's possible recovery.