the trick up here in MI .. z5.. is to get plants dormant.. and keep them dormant ... the plants do not like to go in and out of winter dormancy ... and i bet thats the problem .. especially in the micro climate of this plant vs the others ... in every..lets say .. 10 year cycle.. youll have the mild winter.. and the bad winter ... the rest normal.. the plants are attuned to the 8 regular years.. and stuff happens the other two .. no pic.. so im guessing.. the wall is the problem ... and depending on how close.. its not only reflected sun.. but also retained heat into the night .. so maybe it repeatedly thawed and froze .. causing it to go in and out of dormancy ... longer than others.. and that might have been the issue ... many plants...that have dormant buds.. can regrow .. and with no insult to the relatively massive root mass ... recover rather fast.. and all you need do is train it into some shape you like ... but if it was a grafted plant .. and it dies below the graft.. then you are left to the whim of whatever the root mass is.. and sometimes its not the quality plant you had before ... i dont know anything specific to CMs .... so others will have to chime in here .. regardless ... you have to think in tree time ... and you might have to wait until the next time it blooms to see if its a favorable flower .. and in the mean time.. you just leave it alone ... every leaf is a food making machine.. so it would probably be best to not start the reformation project for a year or two .. subject to CM peeps opinion of how long that should be ... but the bottom line.. if its going to absolutely drive you insane.. because you need a disney perfect landscape.. just get rid of it now ... lifes too short to be pissed off at your garden.. lol .. lastly ... if its planted too close to the house.. and you decide to plant something else .... think about moving away from that wall.. a few more feet ken

Thanks. I was hoping it was sun damage, but I was puzzled by the fact that it was the only plant with the sun damage and also the damage was in the middle of the leaf rather than the outer edges (which would be in line with my past experience). Anyway, thanks for confirmation. I was afraid it was fungal in nature.

do you have the latin name of the tree??? .. its cold tolerance might make a difference ... we usually have to buds from cold damage.. if we want a spring flower show ... sun scald.. on the other hand is a trunk issue ... i have used 4 inch corrugated drain pipe ... to protect from vermin and sun .. but it allowed a lot of empty space for air movement ... but you have a tight nestled trunk ... am i correct in presuming your noodle is tight on the trunk ... i worry about trapped moisture.. and bugs ... im also wondering .. if within that temp range ... whether temps are not really an issue ... WC is bulletproof in my MI ... but flower production can be variable due to spring deep cold affecting the flower buds ... and i am positive it get a lot colder than 26 ... and if i could spell it.. i would tell you i have a kwanzan cultivar ... ken

So what is the answer? Mine is doing the same, SW side, leaves on that side start turning orange yellow in august! White mushroom shelf stuff growing in small places. My neighbor one street over has the same tree. Our houses face the same direction and tree is planted same place. Theirs's is still green. I don't understand. Autumn blaze maples do not always do this. What've I've read is, yeah, it's a goner. But WHAT causes it and WHAT will prevent it. I see plenty of them healthy. Even the garden stores look and say they don't know. Someone has to know. Any ideas would be great or where to go? I know the tree was planted TOO high above ground ---8". So I did infill that with good dirt around 2019 to level it. Perhaps the roots grew up too long since they planted it too high above the soil and just threw mulch on it to hide it. Trees are so expensive to replace. This has been going on for 2.5 years of 4.5 that it's been planted. Soil seems to be fine when checked too.