My chinese elm issue.....

[Fidur]

This is my chinese elm, my first tree when I begun almost two years ago.



It's always been very healthy (some white flies and scales once in a while). But this season ), it's been kind of weaker. 6 months ago, it lost almost 50% of the foliage wich turned yellow and falled. It recovered quickly and three months ago again lost 50% of the leaves, recovering itself at once. In the first episode I was very concerned, so I inspected the rootball. Roots were fine and not jet potbound. So I just tilted the pot a bit (as ryan neal recommends), and took no further action. No actions were taken in the second episode.
Now it has suffered a third fall of leaves (only about 20%) of them, and the tree looks as you can see, a bit weak.
I still don´t know the reason of this periodical massive lose of leaves. It's been watered and fertilized the right way, so I have no concerns about over or underwatering, over or underfertilizing. Also no visible pests or fungus. No root rot or issues in the soil (akadama+lava).....
I've decided to make a complete repot next spring (or maybe sooner) and add some "superthrive" in the root operations( I think this is the fourth season in that pot)
So what do you think?

Edit: It's not related either with heatwaves.

 

[Eckhoffw]

It sounds like you’ve been doing everything right.
Do you use rainwater or tap?
Only thing I could think of.

I’m sure you have it in adequate light.
That’s a tough one.

 

[Fidur]

It sounds like you’ve been doing everything right.
Do you use rainwater or tap?
Only thing I could think of.

I’m sure you have it in adequate light.
That’s a tough one.

I use only rainwater. Light has been adequate as well. It's been in exactly the same place for the last two years...As I said, the tree recovered foliage in the first and second episodes, so maybe it will grow again a third time....(have doubts about it at this point of the season).
Some other views:

 

[ShadyStump]

Does it go dormant in winter in your climate?
Even if other Chinese elms don't have problems there, every tree is a little different. This one may feel like it needs a nap.

 

[Fidur]

Does it go dormant in winter in your climate?
Even if other Chinese elms don't have problems there, every tree is a little different. This one may feel like it needs a nap.

It goes a bit dormant in winter, but anyway this tree has been succesfully living in my climate for at least 20 years....

 

[ShadyStump]

It goes a bit dormant in winter, but anyway this tree has been succesfully living in my climate for at least 20 years....

Well then it's not likely that.
Maybe put it in a cooler, shadier spot for the winter just to give it some help, just in case.

I'm really at a loss then.

 

[VAFisher]

Are there any dark or mushy leaves? Any black spots on the leaves? Or do they just turn straight yellow and fall off?

 

[Paradox]

Anyone think this could be a mineral deficiency?

 

[Fidur]

Are there any dark or mushy leaves? Any black spots on the leaves? Or do they just turn straight yellow and fall off?

Just turn yellow and fall. No black spots

Anyone think this could be a mineral deficiency?

It could be, but about a month ago I put some micronutrients (Fe, Mg,....). Even so I will use a bit more and probably some superthrive as well.
Anyway, the tree is not very very weak, just a tad. I don't fear for it.... I think it will be fine after some repotting and care.
Thanks for your insights!

 

[ShimpakuBonsai]

I use only rainwater.

A little bit offtopic but how do you collect and store enough rainwater in your area to water your trees the whole year around?

 

[Fidur]

A little bit offtopic but how do you collect and store enough rainwater in your area to water your trees the whole year around?

I collect the rainwater from my roof in a 500 liters deposit. Then I use a pump to send it to my bonsai garden hoose. But you're right, I have 2 months in summer in wich I have to use a reverse osmosis system to fill the deposit.
Should my deposit be large enough I would only use rainwater...

 

[ShimpakuBonsai]

Ok thanks. Have you shared pics of your system on the forum? Maybe I missed those.

 

[rockm]

Looks to me like a soil/root issue. The soil looks compacted and/or too dense--despite your inspection. The surface moss/liverwort growth is a sign the underlying soil is staying too wet...When was this last repotted? Is this tree inside or outside? How often are you watering?

 

[Colorado]

I would guess it is related to being the 4th year in that container. It’s not necessarily detrimental per se to be in the container 4 years, but at some point the tree will start to decline a bit and indicate it’s time for a repot. Perhaps that is what you’re seeing. Just a guess.

 

[Bonsai Nut]

I have lots of Chinese elms, across a number of different cultivars/varieties. I regularly experience the issue you describe. It seems to be more prevalent in the summer than in either the spring or the fall. Initially I attributed it to wet foliage and/or some type of fungus, but now I think it might be related to timing of my pruning. It only seems to happen to trees that I don't prune - i.e. that I allow the foliage to extend. If I prune the foliage aggressively and pinch extending tips, I don't have the same problem.

Good news is that it doesn't seem to be a permanent problem, and I have never lost a tree from it. The solution seems to be to prune the tree and defoliate it... at which point it pushes new growth that doesn't have the same problem.

Looking at your tree, I would say that it would benefit from detailed pruning to open up the interior and let sun and air reach the interior of the foliage pads.

 

[Emeraldtarpon]

Im wondering if its red spider mite...are there any very,very fine cobwebs amonst the foliage anywhere (like very fine silken thread)?
They can also hide behind the bark as it peels away from the trunk.
They are incredibly tiny so can go unseen until the damage starts to show.....like its just happened out of nowhere.

 

[Fidur]

I have lots of Chinese elms, across a number of different cultivars/varieties. I regularly experience the issue you describe. It seems to be more prevalent in the summer than in either the spring or the fall. Initially I attributed it to wet foliage and/or some type of fungus, but now I think it might be related to timing of my pruning. It only seems to happen to trees that I don't prune - i.e. that I allow the foliage to extend. If I prune the foliage aggressively and pinch extending tips, I don't have the same problem.

Good news is that it doesn't seem to be a permanent problem, and I have never lost a tree from it. The solution seems to be to prune the tree and defoliate it... at which point it pushes new growth that doesn't have the same problem.

Looking at your tree, I would say that it would benefit from detailed pruning to open up the interior and let sun and air reach the interior of the foliage pads.

I think you can be rigth.
This season I wanted to get a more "naturalistic style", so I decided to let it outgrow its "artificial" former shape. I only pinched the very long branches.
So, probably I'll be prunning and defoliating in some appropiate moment next season

 

[Fidur]

An update on this issue. Tree was in a down trend, so I finally repotted it in january. I saw no obvious problem on the soil, only some rounding roots. I trimmed about 1/3 of the roots and pinched a bit. That's all.
As you can see in this today's pic, it has beautifully retrived health....



I guess a repoting was all it needed....

 

[Mapleminx]

All your trees in this pic are so pretty. And I see El Toro is still going strong in his guarding of a tree.

 

[Mapleminx]

All your trees in this pic are so pretty. And I see El Toro is still going strong in his guarding of a tree.

Darn you, you make me want an Elm now . I have never been drawn to them before but that’s so pretty!