Japanese Acer Palmatum-Leaves scorched/burnt

I have a small j. maple, 4-5 years old. It is a nursery plant and the variety is called "Wendy". Unfortunately the tree at the moment has almost all of her leaves scorched and marginally burnt. I'm afraid I can see only one or two new buds extending new leaves..., it's growth has ceased.

I have always thought that j. maples are damaged by direct sunlight and wind, but searching for evidence about the problem of my tree I have read the following concerning growing in the ground :

The argument that Japanese maples burn in full sun is nonsense and has nothing to do with the intensity of the sun but rather the quality of the root system. Commercial nurseries in New South Wales; Australia, the North Island of New Zealand and South Africa all grow Japanese maples out of doors with no shade cover without any ill effects – it would not make financial sense to grow them this way if they were continually getting scorched. In mainland USA the only place where Japanese maples are likely to encounter problems is southern Florida and that’s down to problems in the winter rather than what happens in summer.

The most common cause is excessive watering in summer, either on it’s own or coupled with a poorly draining soil. Not watering at all and the application of a mulch ensures there is always going to be an adequate supply of moisture at the roots. Poor drainage also compromises a Japanese maple in winter, causing roots to rot and the telltale signs of damage to appear the following spring. Source: http://japanesemapleguide.com/should-a-japanese-maple-be-grown-in-shade/

I grow this j.m. into a pond basket and a free draining substrate. I feed with organic slow release and organic liquid (seaweed extract) fertilizer with micro-nutrients and trace elements every 10 days as a foliage spray and watering, too. I water the tree every other day. It is kept at my balcony, sheltered from winds and in dapled shade.

In another thread here on IBC I read the following (by Marcus Watts) :

... ...Japanese maples are a good test plant to have though, as elevated pH really affects their leaves.
... ...I suspect maples (maybe beech) are very susceptible to ammonium toxicity early in spring, certainly the Japanese practice this approach.
... ...I think fertilizer balls are an excellent way to feed plants, I’m a firm believer that continuous feeding with frequent flushing of the root ball is the way to maintain healthy, vigorous growth.
... ...This is why I say don’t fertilize maples in the first three weeks of growth in spring.

Will you be kind enough as to provide some information about this problem of mine and/or any solutions/suggestions.

Thank you in advance.

I would think Greece is too hot and sunny for Japanese Maples, they tend to like cool/cold weather and not as much sun. I grew some Japanese Maples for a few years here in Florida, they always suffered, even our native Maple suffers, the Japanese Maples finally died. Try the coolest, most shaded, outdoor location you have.

Billy, thanks for your input!
The strange thing is that the last two years it did not have any problem... but this running year it seems suffering although temperatures are not so high yet.
And consider also that it stands at the very same location.

Dear Alexandra

I have more Japanese acers...In Denmark can it be quit warm during summer, and my acers is standing in full sun all the time..But I am sure, it is not hot like Greece.

The only way they scourche their leaves, is when it has rained, or I sprayed water on NEW SOFT leaves, and they like glue together with the water, because of too much density in the crown. The new leaves rot a little, and soon it looks like the sun scourshed them.

If the trees are protected from rain and spraying untill the leaves has hardened , will they not scourche.
Hop it is usefull

Kind regards Yvonne

Hi, dear Yvonne!

Yvonne Graubaek wrote: ... ...If the trees are protected from rain and spraying untill the leaves has hardened , will they not scourche.

Yes, of course this is helpful! Thank you very much!
I collect as much of information as I can

Most of the areas cited in your first quotation are much more humid than you will have in Athens most summers. I rememeber my shock (and a certain amount of suffering) after my first visit from VERY humid Florida. Imagine what an understory tree like Acer palmatum must "feel."

After all, there is full sun and then there's full sun, low humidity, and drying winds.

(I know little about the effects of chemicals on A. palmatum, though I do know that many kinds of maple leaves are susceptible to chemical insult.)

You first quotation also seems to be discussing maples grown in the ground where their roots can have a full, wide run. Yours are in containers and in pond pots and loose soil to boot, where the root ends also may be affected by warm dry winds. I think there probably can be no comparison between the two situations.

I suspect Athens summers will always be a bit tough on your maple and recommend some kind of light shade and keeping them out of direct wind on that balcony.

JimLewis wrote:... ...though I do know that many kinds of maple leaves are susceptible to chemical insult... ... and recommend some kind of light shade and keeping them out of direct wind on that balcony.

Thank you, Jim!
Indeed, you are describing the position my maple is sitting.
However, my wonder is as I said above, why now and not last year?
I have used some chemical spray on my maple's "neighbour", a Phillyrea latifolia which had an aphids infestation and the foliage had become sticky. I am afraid, the spray cloud had also covered the maple's foliage.

Do you think it will recover and go on with new growth?

My advice, as I grow several different Palmatums c/v's (some more touchy than others) is to first STOP spraying ANYTHING on the leaves. Organic fertilizers are ineffective for foliar feeding anyway.

If you can take a photo I might be able to tell you whether your dealing with a fertilizer/water quality issue and thats whats causing your marginal scorch which I believe it could be as you say the tree is out of wind and in dappled shade. If as you say EVERY leaf is damaged it's a good bet the problem is systemic rather than external. Ie salts in water or fertilizer burning the leaves.

Also; advice that you read about growing Palmatum in the ground wont be directly relevant to growing them in a pot. Case in point, we trim roots at re-potting, Japanese maple in the ground don't have root restrictions as they search for water...


But mostly stop spraying the leaves.
-Jay

Thank you very much, Jay!
When I'm back at home I will shoot some leaves and upload the photos.

Well, the IBC thread I was referring above is this and in fact it was not Marcus Watts BUT you the poster of the above mentionned quotes...
So, now everything is put in its real dimensions

my nellie wrote: in fact it was not Marcus Watts BUT you the poster of the above mentionned quotes...

Those quotes are from Paul (63pmp) who is a hydroponic grower in Australia.
-Jay

Yes of course, you are absolutely right Jay!
Hehehehe I should have posted using the "Quote" button, then I wouldn't have made such a perplexity
I am sorry, anyway....

my nellie wrote:Billy, thanks for your input!
The strange thing is that the last two years it did not have any problem... but this running year it seems suffering although temperatures are not so high yet.
And consider also that it stands at the very same location.

I think that just as in people stress builds up in plants. The plant might not show the results of that stress for a few years but then as the stress builds up and weakens the tree other things happen including fungus. I kept some Japanese Maples alive for ten years, they didn't grow much and they showed signs of stress every year, they finally gave up. We find that a lot in trees that we try to grow that are not really adapted to our climates. Stone fruits such as Apples, for example. There are a couple of Apple varieties that don't require a lot of cold temperatures to set fruit, and they will survive and produce fruit in the ground for us, but they eventually die from the stress and are not very long lived.
My native Florida Maples are beginning to show stress in their leaves right now and will defoliate at least once during the summer, maybe twice. The native Maples in the ground show the same signs.

@ Billy
I see what you mean...
Perhaps, we need to be oriented at our native species no matter how much we like species thriving elsewhere in the globe.

@ Jay
These are some photos of the leaves. I hope they are clear enough...

hi,
its Marcus this time

This is a simple one - the pond basket is the problem - you are growing an acer not a pine. To keep the leaves in nice condition you need a steady supply of moisture and humidity. The soil mixture you use needs to hold moisture and air so the tree does not go very dry between watering but does not get root rot in wet seasons if you have one. you had no problem last year because the tree was smaller and had less roots and less leaves - now the roots in the basket can not provide the moisture required by the greater number of leaves.

An acer grows at its absolute best if the width of the pot virtually matches the width of the branches - this underpins the branches with roots and humidity. A soil that can hold moisture is essential (i use akadama and kiryu as the water holding particles but each to their own on soil components) and a cool ceramic pot rather than plastic or pond basket will solve the problem.

as the tree progrresses you will not worry about the first leaves so much as they are fully or partially defoliated, reduced in number by half or even cut in half every year. the leaves to look after are the second flush of inner ones.

cheers Marcus

Hi Marcus!

Well, well, what can I say?
It seems you are correct with your reasoning of the problem. Last year the maple was growing into a plastic pot and it has been repoted early in spring into the pond basket for better aeration of the roots. You see... the ignorance of a beginner is the reason I thought this method of growing (pond basket or strainer) is applied to every species.

Thank you very much for your response!

marcus watts wrote: ... ...and a cool ceramic pot rather than plastic or pond basket will solve the problem... ...

You are referring to the next repotting, right?
Or perhaps I can slip pot the tree into a ceramic pot right now?

My next question :

marcus watts wrote: ... ...as the tree progrresses you will not worry about the first leaves so much as they are fully or partially defoliated, reduced in number by half or even cut in half every year... ...

My tree is in training and I cannot perceive whether I have to cut off the damaged foliage or not, since the leaves haven't fallen off their stems... Would this defoliation add on stress to the tree?
What is your suggestion/advice?

my nellie wrote:

marcus watts wrote: ... ...and a cool ceramic pot rather than plastic or pond basket will solve the problem... ...

You are referring to the next repotting, right?
Or perhaps I can slip pot the tree into a ceramic pot right now?

hi,

No, dont wait until the next time, do it straight away. There is no need to confuse repotting with rootpruning when it comes to repotting time. Any tree being developed, grown on, potted up etc can be moved at any time - I've did the big red acer middle of last summer in full leaf to a wider pot with no ill effect. (Once a tree is in the right sized pot repotting will need rootpruning - then I time it to coincide with the new buds swelling)

For the next point about the leaves.....
Do you have a plan yet how you want the tree to turn out? If you do then for now just concentrate on developing the trunk to the thickness you want and the main branch thickness. Do this by letting the tree grow quite freely, but continue to remove multiple twigs from the top, now and again shorten very strong upward growth too, as this will weaken the lower branches. Once the trunk is good virtually every branch on the tree will be cut back to shortish stubs and the branches grown again.

This is the time to thin the outer leaves etc so the inner shoots get light. This may be a few years away on your tree, depending on how you want the trunk.

hope this helps a little.

cheers Marcus

marcus watts wrote: ... ...hope this helps a little.

Good morning, Marcus!
In fact it helps a lot! Because you know, there is a great difference between having read about anything and having the knowledge to do it right. Although I already supposed what I should do, there is always the doubt of being mistaken in my judgement because of lack of self confidence as a novice...
So, thank you very much for your help! And thank also IBC!

hey im arman and im new on this forum.
i just bought a Japanese maple tree with 6 ft height.and im planning to keep it inside near a window which air circulation is fairly good.
there is about 5-7 hrs of indirect sunlight and the cape of tree in is shadow of my roof.no fertilizer applied yet.
i just noticed that some leaves are scroching.
i didnt sporay water on leaves.the plant is not repotted since i bought(1 week).
its a little warm and dry in this location(isfahan city).
well im told that the tree should be kept oin the bal;coney bu to be honest i like it indoor.
i transported the tree in a open vag and it had some air draft stress while transportation
im a little bit worried about my tree...
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This is not a bonsai, but keeping this tree indoors will kill it. It needs to go dormant in the winter and it needs more then indoor light in the summer.

yep Dear Billy,
but any way to keep the tree inside or i should transport it our door with no exception?

Always outdoors, unless you live in the extreme north, where you live does make a difference.

well i transfered my acer out side..there is no Direct sunshine but there is a bright place in the balconey.
90% of my acer leaves are scrotched and tree sticks is not hydrated.
some dude told me its a Summer dormant but im afraid.he told me to keep it there and tree is getting sleep in the summer.
well any advice?i have no place to put it there to get less sun light except indoor near window.thanks for ur response

Keep in mind that the Japanese maple is an understory tree in nature. That means it normally grows under the shade of other trees. And it's native home is Japan is a cool, damp county. A Japanese maple will struggle in the hot, dry climate of Iran. (as I understand your climate)