Ginkgo biloba yellowing leaves & stress

[NathJB]

Hi

I’m new to this amazing forum. I’m reaching out as I have a Ginkgo biloba that is just over 28 years old. It has been with me since 2002 and has always been a strong and hardy tree. Repotted this specimen at the end of August, and all was healthy and fine with healthy roots and the subsequent pruning. Of note the last time I repotted this specimen was approximately 2 years ago.

I was sure to apply a diluted amount of Seasol at the time of repotting. The last two weeks I noted a small cluster of leaves yellowing on the middle left side of the tree. I put this down to a bit of transplant shock. The last two days the top most left hand side has started to yellow and some of the leaves going a tad limp in some spots. I have attached some photos for reference. As noted in the attached photos I have explained that the lowest branch below the yellowing top canopy is healthy and green.
Thanks for any advice and assistance in advance.

Regards
Nath

[shibui]

I find ginkgo very tough. I can remove the majority of roots and they still keep growing so I doubt that simply root pruning would have caused this die back.
As it is confined to one side of the tree I guess it is related to a root problem but I have no idea from the info given what that might be.

You have not given us a look at the pot or the potting mix you use, either of which could have a bearing on the problem.
I assume that watering has not changed from whatever was successful in the past but watering - either too much or not enough - could also cause symptoms like this.
Any chance that there was some damage to either trunk or a major branch recently? Definitely check the trunk below the yellow section to see if there is any slight change to the bark. Dead bark begins to look slightly more wrinkled and sunken compared to healthy bark.

Not sure I have anything else to offer at this stage.

[NathJB]

Thanks for your speedy reply. Apologies for failing to paint the complete picture.

I too have always found this tree to be very resilient and eager to bounce back following root pruning. This is what I am at a loss as to why this set back has occurred, and some time after the repotting.

I have been growing this specimen in the same mix for the last 6 or so years - Bonsai Environment - and the same pot. It is still located in the same outdoor position, receiving the same amount of sunlight and air flow. It is also experiencing the same watering routine. I had noticed that for a short time following repottimg the draining following watering would take a while. So, this may have caused a lack of air around the root mass? It cold also be that the last bag of soil may have a changed or been too fine and caused compacting?

I have included a photo of the bonsai in its pot from last year.

What I am thinking is why only the left side of the bonsai is experiencing the leaf distress. Part of me thinks that of the tree was suffering root issues that the whole tree would be showing the same symptoms?

As for obvious bark damage or changes there isn’t anything to see. All bark is uniform and of the same firmness.

Part of me also thinks if I should remove the tree from the pot so as to see what is happening at the root level. Would this be wise? I don’t want to stress it further.

Cheers
Nath

[Akhi]

Looks like transplant shock more than anything to me, surprised you repot GB when in full leaf, I did that to my seedlings once and the leaves all went limp. Lost a few and went dormant over that summer and autumn, but bounced back next spring. So if everything else is fine, just keep up the post transplant treatment and sit back and hope for the best.

[NathJB]

Looks like transplant shock more than anything to me, surprised you repot GB when in full leaf, I did that to my seedlings once and the leaves all went limp. Lost a few and went dormant over that summer and autumn, but bounced back next spring. So if everything else is fine, just keep up the post transplant treatment and sit back and hope for the best.

Hi
Thanks for your reply. The repot was done in August, so the bonsai was still dormant. This is why I’m so worried as initially all new growth was as normal and now only a few days ago I am presented with this worrying development.

Cheers
Nath

[shibui]

What I am thinking is why only the left side of the bonsai is experiencing the leaf distress. Part of me thinks that of the tree was suffering root issues that the whole tree would be showing the same symptoms?

General root problems affecting the entire root mass would show up as overall leaf problems above. This would be typical for root rot or problems associated with soil conditions, watering, etc.
Damage to one major root can often show up as localized leaf damage as there is usually a strong connection between roots on one side of the tree and the branches directly above. Trees do have the capacity to re-route sap flow but sometimes not quick enough to save some branches.

With only the one side symptoms to go on I'm leaning more toward some localized root damage or infection. I have seen something very similar in a Japanese maple where the lowest branch died. Afterwards I discovered the roots below were also dead and eventually a section of the trunk between the 2 also showed up as dead. Not sure whether the branch caused roots to die or vice versa because you can only see the branch until it is all too late. Good news is that tree is still alive and growing well albeit with a dead section of trunk so fingers crossed that yours will also live through this setback.

I am reluctant to advise to unpot now just to check roots. The new roots that may be growing from healthy roots are very brittle and easily damaged so checking roots may cause further damage. Also not sure what you could do if you do find some symptoms below ground. With care it can be done - I'm not sure the possible benefit outweighs the risk but that's a call you will have to make bearing in mind your experience and level of care you can take during the operation.
You could try a root fungicide as a precaution. Even if that is not the problem it is very unlikely to cause additional harm but if there is something growing it could help.

[Grant Bowie]

I would say definately do not repot, and get some systemic fungicide into it if you can get some.

grant

[NathJB]

You could try a root fungicide as a precaution. Even if that is not the problem it is very unlikely to cause additional harm but if there is something growing it could help.

Thanks again for your input and insight into root to branch relationships. This was something that I was not aware of.

I will take your advice and not uproot the tree. Do you have a preference for the type and brand of fungucide. I do hope that this will assist the recovery and minimise the branch die back.
Cheers
Nath

[juan73870]

I've had success with "Yates Anti Rot", comes in a little yellow bottle for under 20 bucks at most hardware/plant stores. Mix up and spray on foliage. Even if root rot isn't the issue, it shouldn't harm the plant. Good luck

[NathJB]

Hi
Thank you to everyone who has been so very helpful. I do appreciate the timely advice and guidance. This bonsai means the world to me, so the stress and worry has been pretty full-on.

I have now today applied the Yates Anti Rot to the right hand side with the healthy green leaves - I also gave the left side a good drench as well in case the buds and yellow leaves may absorb the treatment too. Upon inspection I have found the probable cause of this decline. A main root that travels directly from the trunk and stressed side of the Ginkgo looks to be a tad soft and mushy just under the substrate. I have added photos.

On a more encouraging note, the buds on the left side are still green atm, even though the yellowing leaves are starting to detach and fall off.

A massive thanks to @shibui for all of your wisdom and ultimately being pretty much so 100% correct on the causes and related symptoms. To know that I may have a good chance of saving not only the left hand side of the 28 years of branch development, but the whole tree, is a massive weight off my mind.

Cheers
Nath

[shibui]

Best not to jump to conclusions until we see more proof. I would still only put the signs down to a 'probable' cause and though survival is likely nothing with living things is 100% sure until it happens.

I'm still not sure what has caused the root to decay (if that is indeed what has happened). It is not something I have seen often in ginkgo so I would be thinking hard about possible causes. Too much water after root pruning? Time of repotting? Possible infection on root shears? Soil type? Physical damage while root pruning? etc. It is very difficult to remember exactly what happened way back months ago but worth taking more notice next time.
Definitely sanitize all tools that you may have used on this tree before using them on others just in case.

[NathJB]

Ginkgo Update

Hi all,
Thought that I would post an update on the progress of my 29 year old Ginkgo biloba.

I’m happy to write that it rebounded this Spring with some very vigorous growth. I’ve been keeping the Seasol and diluted Powerfeed up to this tree. A long stem was shooting out from the top of the canopy, so I decided to trim this to keep the canopy tight. As I do each week, I was checking the trunk, and to my surprise there are a couple of buds developing - and of note one on the side that had died off. It’s amazing how nature likes to balance out.

My only concern is that the bud on the left may be too low. What I’m curious about is what the chances are if I were to remove it and hope to trigger new buds higher up.

I would like to thank the members in this forum for their time and advice, as it’s been invaluable.

Any thoughts and feedback are welcome.

I’m off to the Newcastle Bonsai Show!

Cheers
Nath J

[Akhi]

Great to hear you have a survivor.suggest you let that bud keep growing esp since it’s on that weak side. You could
Potentially layer it side on once it is tall enough.

[NathJB]

Hi Akhi

Thanks for your reply. I have attached a few photos of the trunk with the buds that have begun to emerge. That way it gives greater clarity.

Either way I’m glad that there is vigorous new growth that is robust and responding to the feeding regime.

Cheers
Nath J.

[Akhi]

That’s a lot of lush moss, try keeping the tree with less water, mine struggled when I moved them from Adelaide (drier) to Melbourne(wetter) then I moved them to a coarser mix and kept them relatively dry over winter and they have all grown crazy. I think they need lots of water while growing but relatively dry when dormant.