Japanese Maple - Problem with the unairlayered leaves

[Ozz80]

This spring I bought a medium sized non cultivar Japanese maple tree from a nursery. It was not in the best soil and a few leaves showed signs of underwatering but it was not too much, so I did not bother. I immediately airlayered two of the three main branches (it was 6 weeks ago) while keeping the third branch untouched to supply sugars to the root system and the main trunk. The idea was to reduce the tree in size by airlayers, repot at next spring to a better substrate and while repotting, to check the root system and decide how to progress to create nebari for the main tree (airlayer the main trunk, ground layer or just improve the current root system).

Strangely, branches that are airlayered are stable as they are in the first day (no new shoots but no further browning of the leaves) meanwhile leaves on the branch that is not airlayered are browning and drying at the tips. I am still watering only after the soil is dry, and I recently moved the plant to a more shadowed spot. But I suspect that it will survive when summer heat waves of Istanbul comes.

The first photo with healthy leaves belongs to an airlayered branch. You can see on the third photo that the small shoot just below the airlayer is drying (leaves up on the airlayered branch are healthy). The second photo belongs to the unairlayered one. You can also notice slight chlorosis on some of the leaves. Chlorosis is both on the airlayered and unairlayered branches.

What can be the cause of this problem? Is there anything I can do at the moment?

 

[Bonsai Nut]

Usually when I see tip browning like this, it is a sign of too much sun, or too much dry wind. It can also be a sign of bad alkaline water or alkaline soil conditions. If it is sun or wind, the damage will be worse on outer leaves, or leaves on the front of the tree facing the sun, while inner leaves or leaves on the back of the tree will show less damage. Alkalinity issues will be more general across the entire tree.

I don't know why an air-layer branch would be healthy while non air-layer branches are not, unless it is combined with one of the issues above. Is the air-layer branch on the side of the tree facing away from the sun?

 

[Ozz80]

Usually when I see tip browning like this, it is a sign of too much sun, or too much dry wind. It can also be a sign of bad alkaline water or alkaline soil conditions. If it is sun or wind, the damage will be worse on outer leaves, or leaves on the front of the tree facing the sun, while inner leaves or leaves on the back of the tree will show less damage. Alkalinity issues will be more general across the entire tree.

I don't know why an air-layer branch would be healthy while non air-layer branches are not, unless it is combined with one of the issues above. Is the air-layer branch on the side of the tree facing away from the sun?

Thanks for your reply. Actually I was constantly changing the angle of the pot, so that everywhere gets equal sun. Besides it was previously in a spot where it got only morning sunlight.

Actually the branch is in the middle and as a result it shares angles with other 2 branches. I am posting the photo of the foliage connected to this branch and the small shoot below one of the branches that was airlayered. Everything in the red circles is unairlayered and unhealthy. There are 2-3 leaves with dry tips out of this area.

Previous spot was windy, but weather is not dry here. Eventually humidity rarely falls below 55 - 60 %, reaching 90 % several times. (91% at the moment)

There is no visible damage on the unairlayered branch. So, I am having a difficulty at finding a logical explanations for this.

Do you think I could airlayer the last branch as well, or the main trunk just below the V shaped spot where trunk splits in two?

 

[Ozz80]

Finally, water is slightly alkaline (ph around 7.5). In May, I fed it with osmocote. Seeing the slight chlorosis, I also gave a small amount of chelated iron

 

[Bonsai Nut]

Finally, water is slightly alkaline (ph around 7.5). In May, I fed it with osmocote. Seeing the slight chlorosis, I also gave a small amount of chelated iron

I honestly don't know what else to suggest. I would hold off on starting another air-layer until the first one is successful, and the tree has recovered. If you start an air-layer when the tree is weak or the foliage is partially dry, your chances of success will be lower, and I'd hate to have you lose the entire tree because you moved too quickly.

 

[rockm]

I’d guess that the leaves remaining on the tree were shaded by the air layered portions. They are now exposed to harsher sun exposure and possibly wind/air circulation they had developed for.

The air layered foliage developed higher on the tree and possibly had more exposure. Hence they are not all that affected

Just a guess. Leaves that develop in relative shade don’t adapt to changed conditions. They are replaced by foliage that is.

 

[Ozz80]

Thanks for your responses. I will keep it in shade, water it carefully and wait and see what happens

 

[zita]

this looks to be an osakazuki, quiet sure.

it isnt burned severe and i would keep it as sunny as possible. Osakazukis do have no problem looking burned all over the place for the entire season and still survive easy. Dont remove the leaves, the tree is balancing the situation itself.
It is very common and actually they have to go through that. Next year the osakazuki will already be fine and overnext season it will love and perform great in hot sunshine.
Also, then and only then you will get the amazing red fall colors of what osakazuki is so famous for. Otherwise it will be meaningless green brownish.
However, your tree is very very mildly burned for an osakazuki compared to what mines have gone through, almost untouched.....so do not worry at all. The only thing is, as @rockm has mentioned, they do not like to go up suddenly in sunshine. Some actually do survive extreme changes, burning the big leaves quickly and budding out new small ones in no time.
For example i purchased a little green yamamoji 2 weeks ago that was placed completely shaded and putted it in full sun after hard pruning.
Well it turned dark quickly but now alredy little new buds and absolutely no concerns it wouldnt survive.

 

[Ozz80]

this looks to be an osakazuki, quiet sure.

it isnt burned severe and i would keep it as sunny as possible. Osakazukis do have no problem looking burned all over the place for the entire season and still survive easy. Dont remove the leaves, the tree is balancing the situation itself.
It is very common and actually they have to go through that. Next year the osakazuki will already be fine and overnext season it will love and perform great in hot sunshine.
Also, then and only then you will get the amazing red fall colors of what osakazuki is so famous for. Otherwise it will be meaningless green brownish.
However, your tree is very very mildly burned for an osakazuki compared to what mines have gone through, almost untouched.....so do not worry at all. The only thing is, as @rockm has mentioned, they do not like to go up suddenly in sunshine. Some actually do survive extreme changes, burning the big leaves quickly and budding out new small ones in no time.
For example i purchased a little green yamamoji 2 weeks ago that was placed completely shaded and putted it in full sun after hard pruning.
Well it turned dark quickly but now alredy little new buds and absolutely no concerns it wouldnt survive.

It is a relief to read that, thanks for your response !!