Black bark on bihou

I recently transplanted my bihou and noticed this morning that the trunk is blackening on the backside of the tree. It looks like it’s spreading upward. I want to save this tree so am wondering if anyone knows what is causing this change in the bark and if it can be treated. I have read that bihou have problems but am willing to work hard to help it recover. Thank you for any advice.

 

Timing makes me expect this to turn out to be bacterial blight (Pseudomonas).

 

Hi,

I’m sorry to say it looks pretty terminal to me.. I had it on one of my trees but it was isolated to a couple of branches so I cut them off several inches below..some helpful contributors on here advised me to take it back..as they thought mine would be terminal..but from your photos it looks like it’s down the main trunk.id isolate it from all other trees you have and be careful not to contaminate other trees with soil, water or pruning equipment.sorry these are not bright, optimistic thoughts.

 

Bonsai enthusiasts love to try new cultivars to train as bonsai like 'Sango kaku' or 'Bihoo' (or 'Bihou'), but the latter is said to be prone to fungal diseases from what I've read. Yet, I bought one in 2015 (not for bonsai), and four years later, this one seems to be perfectly healthy.

 

Mine had lots of tip dieback until I fertilized it.

 

I have a couple of these only small about two foot or so, both have had die back, one is now doing much better than the other. How did you fertilise it?

 

'Bi hoo' (spellings vary) is difficult enough for pseudomonas that some leading grafters have stopped propagating it.

I have one that blackened in the second year after planting. One of the big black spots was just above the graft line,almost totally girdling the trunk. There was only a small strip of living bark, which looked quite nasty too. I cut a lot off, pulled it into a big pot, did the usual copper treatments. The following year I left it in shade and forgot about it, (expecting it to die), and was astonished to see in late summer that it was growing enthusiastically and had heeled over a little of the big hole. It's still doing fine, though there is still a hole about 1/4 around. Something that big takes a long time to heal! Just checked, I pulled it in 2016.