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Trunk

all previous pics were of tree #1 and now these are of #2

Back to #1

Example of dieback with the spots

Close up

Most of the white stuff appears to be lichen. If so, not a problem.

On the other hand, on my Japanese maple, I notice that some of the upper branch surfaces are whitened by not damaged by any disease.

In your final 2 images, the dieback could be due to Pseudomonas or minor cold damage or Pseudomonas secondary to minor cold damage. (How cold has it been where you live?)
If so, wait until the weather warms to prune off the dead stuff by cutting an inch or more into live wood,

It hasnt been very cold...60's day and 40's at night.

So just prune when warm? Why not now? Would a bactericide help?

I took down my shade

==>>> what does this mean ... did you harden them off to a change in sun intensity ...???

frankly ... it looks like my JMs after a cold MI winter ... i usually blame it on cold blistering winds in winter.. especially at dusk.. after a day of sun thawing one side of the plant ....

so.. that is agreeable to your guess of sunscald ...

but i do understand.. that your z9 idea of what is cold.. has nothing to do with my MI idea of cold ..... single digits with 20 to 40 mph winds ...

my gut would say... no disease on dormant trees in winter ... but your z9 idea of winter.. is what i call late spring ... lol .... so i offer no help in that regard ... those are temps when we shed the snowmobile suit.. and pull out the shorts.. after a MI winter... lol

good luck

ken

Yes I did harden them off under shade then took the shade down... I thought I only needed the shade up when the heat and sun were intense--i took them down as soon as it was officially winter. Was that a mistake???? Shade is back up since we are to have some close 80 degree weather this week.

Im glad it doesnt look like disease! Does the amount of sunscald look like the trees can recover?

Yes I did harden them off under shade then took the shade down... I thought I only needed the shade up when the heat and sun were intense--i took them down as soon as it was officially winter. Was that a mistake???? Shade is back up since we are to have some close 80 degree weather this week.

Im glad it doesnt look like disease! Does the amount of sunscald look like the trees can recover?

I see the white spots every year, and get some minor dieback every year. However your last few pics suggest something more at least for those branches. I would prune those out ASAP if possible. Probable need to go 3-4" below the last visible signs, and dip your pruners in Isopropol (rubbing) Alcohol of Hydrogen Peroxide between each cut so as to be sure not to spread any around causing new infections. Also no overhead watering.

Arktrees

Japanese maples generally have thin easily damaged bark. Protecting them from the combination of winter sun and, especially, wind is always a good idea, even in a warm climate.

Yes I did harden them off under shade then took the shade down... I thought I only needed the shade up when the heat and sun were intense

==>>> i dont understand how you hardened them off to sunlight.. and then took it down ...

e.g. if you had 55% shade clothe ... and then remove it.. then you are in creasing sunlight ... i am going to guess... 55% ... and that MIGHT be problematic ... i dont know ...

but the point is.. you changed the plants CULTURE ... and then noticed changes.. one would think.. its more than coincidental ...

you really dont know what winter is.. in your z9 .. lol ... its been single digits here in MI most of this week ... and as i said ... some of your stuff.. looks like what my JMs .. and roses used to look like ... from winter sun and wind dessication ....

i dont really understand.. why you removed the shade cloth ... why it couldnt have been left there ...

i really have no answer for you .... all we can do is speculate ...perhaps you ought to put the cloth back up ... whats to lose????

maybe a pic of the whole setup.. rather than just single plant pix.. might inspire other ideas ...

ken

It is a patio umbrella, 11 feet wide and about 13 or 14 ft high or so. Shade cloth is not allowed by our HOA so I had to use something that still looks "pretty" and acceptable to the neighborhood while providing shade. They still get some morning sun from the sides so I think it's been sufficient. Thing is, my husband gets annoyed with the umbrellas and likes when they are closed out of sight, so whenever it seemed cool or cloudy, I'd close the umbrellas. There was one day that I forgot to open them back up and the Tsuma Gaki got fried in 110 degree weather, ughh... I didn't notice the damage to the bark at the time, so maybe it happened that day, or from the open close open close crap I did all season. And then when it cooled off for good I thought it was safe to keep them closed until the sun and heat gets intense again. So... it's sounding like I should just keep the umbrella's open for good?

Yeah you're right I don't know what winter is! LOL, I was scared that it wouldn't get cold enough out here to get my trees to go dormant, but luckily one night time temps dropped to the 40's the leaves did turn brilliant colors and eventually fall off. Phew! But then revealed to me all this bark damage. Waaa!!!

Arktrees, you said I should trash the Peaches n Cream from my other thread. These two trees were next to the little Peaches n Cream. One is a Tsuma Gaki the other is a Shigatatsu Sawa. And there was plenty of watering overhead with the hose to blast off bugs and dust during the season. Each of these specimens was close to $400 each. One was shipped to me on a pallet from Oregon (I'm in southern CA). The other was in a 24" box from a local pricey nursery. So I'm going to be pretty bummed to lose them or for them to be disfigured. You mentioned that the last few pics suggest something more, do you think pseudonomas syringae????

So should I prune off branches that looks like pics 5 and 6? Honestly a lot of them look like that. Most. I'd probably have to prune off everything. I have other expensive JM's in the immediate area so if I need to trash these two as well, I'd do it to save the others. I'd be bummed, but I'd do it. Should I?