Japanese Maple dying branches

[Deep Sea Diver]

Good job.

Yet… if it’s got root rot the core could be softer then usual. But I’m optimistic. I’d go ahead with H2O2 and fill the holes lightly as suggested. The holes will increase aeration in the core, which will help at that.

cheers
DSD sends

 

[LiquidTension]

Simply a wonderful video all around

 

[clem]

i think your tree is very weak so it loses branches. Is it a cultivar ? or is it an Acer Palmatum ?
If it was mine, i would remove the rootball from the pot, to check if there are root rot or white rootlets.
If there are white rootlets, i would put it in a large but flat woodbox, with akadama+pumice + organic fertiliser on the surface (for the roots and leaves to grow). And if the tree make new shoots in summer, ( = good sign of recovery) then fertilisation again
If there is root rot, i would remove the soil and cut all the rotten roots, and then put it in a flat&large wood box to recover faster.

 

[bwaynef]

This looks like a root issue. I doubt your tree is going to die, but I'd bet money you're going to lose those suspect branches. You have JUST entered the danger zone for repotting. A week ago it would probably have been safe to do still. Now, aftercare would have to be excellent. Think bright shade while maintaining moderate temperatures and a wind block. Ideally, a greenhouse that doesn't get overly warm. And still, if you were to repot it now, you couldn't cut into the roots aggressively. (Aggressively pruning the roots tends to yield an aggressive response which this tree could benefit from.) All that said, I think I'd wait, particularly since you said the soil wasn't terribly compacted.

(Also, its a little hard to see from these angles, but you may've potted the tree too high, ...which could be part of the problem causing the roots right under the trunk but above the edge of the pot to die off.)

I'd remove the live moss. Chopstick and backfill any places where the soil seems compacted. One treatment of h2o2 & h2o 1:1. Tilting it on an angle makes good sense as well. Then I'd look into the bio/pro Danu product. Its a biological input that people are raving about on your side of the pond. Peter Warren seems to be spearheading the efforts, but Harry Harrington has reported good results from it as well. I believe its used as a root drench as well as a spray. I can't get that product in the US, but you ought to have access to it.

And if the timing was earlier and it wasn't in leaf, I can't recommend strongly enough the treatment of Japanese Maples with Lime Sulfur. Its done as a dormant spray though, and will likely burn leaves if applied now which this tree can't afford to replace. But when done while dormant, it is a tool that I credit with reducing/preventing/curing lots of unhealth in my Japanese maples (and some other deciduous). I don't enjoy the application (it smells like rotten eggs) but I won't go a year without applying it after seeing the difference it makes. Next winter, make sure to treat at least your maples, but all your deciduous will benefit