AusBonsai

Hi forumers, I have two Japanese maples that are starting to struggle:
From tree 1:



Most of the leaves on this tree are in this condition
This is not quite in full sun, does get some shade but is against a brick wall.

From tree 2:


This tree has put on quite a bit of growth but leaves are not looking the healthiest

Both tree's are in an organic potting mix with fine mulch over the top. Every few weeks they get some season and worm pee, and a handful of dynamic lifter type fert every now and again. They do not get any slow release fert. They are in growing pots not bonsai pots.

Any help on what is a)happening and b) how to treat it would be much appreciated.

Thanks in advance
Angus

I dont use Seasol on my Maples. It seems to murder em. That and they need filtered light or indirect light when theyre immature.
If you do use a tonic/fert make sure its diluted enough (very weak).
Those leaves look burnt, more shade!

With maples ive noticed that the leaves survive best in the environment they sprout in. I.e. My maples that were dormant in full sun and sprouted in full sun do well in full sun. If they sprouted in shade thats where theyll do well.

Misting wouldnt hurt either...

-Mo

I'd question the heat impact being a Japanese Maple.
These guys very easily burn from either sun or wind during Summer.
If you look at any of the outdoor tree's in your neighbourhood you'll notice all of them will likely be burned to some degree.

The brick wall in particular could hold quite a large amount of radiant heat and may help burn the leaves.

How close are the tree's to the wall?

Wind protection is pretty key as well..

I'm not really familiar with any effects of over fertilizing but the description of "a handful" of DL does worry.
What do others think?

I have all my Maples under dappled Light and they still got leaf burn. that is what this looks like to me
I defoliate them after Chrissy so they are shooting a new crop of leaves now that are not burnt, so should look good for Autumn.

I only use seasol after repotting and root pruning

Ken

I, like Ken, defoliated my maples just after Christmas and then placed in dappled sunlight.

Is it too late to defoliate-to eradicate the ill leaves. They can then go to their new home in dappled light.
They are protected from the wind but does get quite warm.
"A handful of DL" sorry perhaps an over exaggeration. Any particular frets that are better for maples, and ill cease the seasol/tonic stuffs.
Thanks for all the swift replies.

I use Seasol on all my maples every week and have new leaves on all of them including Tridents,all my trees get the same treatment,and nothing else, no problems at all, in my opinion seasol is the greatest thing around for horticulture.

First thing Isitangus is to do no harm. In most cases leaf burn will not kill a tree. But what you do in turn can have a major influence on the health of a tree. The rule is Never defoliate a tree that is not healthy. Although defoliating the tree may bring a fresh crop of healthy leaves you must remember that any green on those burnt leaves is still producing energy and if you remove them the tree will need to use energy to replace them before it can make more energy again. Does the tree have enough stored energy to do this.
The only way to know this is experience and also knowing the tree. Does it have a good set of roots is it suffering from any other stresses. If it puts out a new set of leaves will they now also get burnt and the tree is left with no leaves and no stored energy.
All these things go together and you must remember the tree will do what it thinks is best for it's health. It may decide to make do with what is left of it's leaves or it may decide to add some more and the old leaves will still produce energy as well as shade the new growth. If you are just growing the tree on at the moment then I assure you the risk you take by defoliating a tree you know little about is done for no advantage at all.
If you are a very experienced grower and want to show the tree (or maybe just display in your own garden) then yes defoliating is a possibility but it comes with risks. Experienced growers can minimise the risk but never be rid of it.

Experienced grower-not
Tree ready for show-not
Going to defoliate-not
I assume they have a healthy root system (?) but not going to repot to check it out. I plan on repotting and checking out the roots during this dormancy.

I think my plan is....move them into dappled light-shaded area.
Perhaps a weak seasol drink and a small amount of slow release food.

Appreciate all of the useful advice and feedback

Shock and horror I find myself agreeing with Bretts

Your plan

Experienced grower-not
Tree ready for show-not
Going to defoliate-not
I assume they have a healthy root system (?) but not going to repot to check it out. I plan on repotting and checking out the roots during this dormancy.

I think my plan is....move them into dappled light-shaded area.
Perhaps a weak seasol drink and a small amount of slow release food.

is very sound Isitangus and just what I would recommend. Lets see what they look like next winter.

They have been moved to under the shade of my 3mtr+ maple tree, just had a nice drink courtesy of the storm coming through western Sydney. Will see how they progress...