My Chinese Elm is driving me to drink - defoliation with each fertilizing attempt

[Toshi]

Last summer I started using BonsaiPro 7-9-5 after using Jack's 20-20-20 for a number of years.

The first time it fully defoliated was Sep 2021 but I attributed this to underwatering. I left it to recover for the next few months and began fertilizing once it put on significant growth, around Jan/Feb. Again, the tree fully defoliated.

I let it recover and grow vigorously without fertilizing until about 2 weeks ago. I was using the recommebded dose and adjusted to half and once again, it defoliated.

I follow the same method with every tree i have, give them a soak with just water then after 5-10mins water with my liquid fertilizer. I have Japanese maples, bald cypress, microcarpa, plectranthus, premna, portulacaria, schefflera. I've used the same exact dosage with every tree but my Chinese elm is the only one that reacts this way to fertilizing.

I feel i can reasonably attribute the leaf drop to the fertilizer but I'm no expert by any means. Anything I'm overlooking? Any input is appreciated.

 

[waydeo]

Try diluting to 1/4 strength. Try a different liquid fertilizer. Try a slow release fertilizer like osmocote or bio gold.

 

[caffeinated]

I can't imagine that it has anything to do with fertilizing even if you're applying a little too much. But I don't have any other idea what it may be either. I've neglected some elms and done terrible things to others, but they only defoliate come winter. Are they living outside, getting good sun?

 

[Shibui]

I'm also surprised that Chinese elm reacts to fertilizer. I've never seen that here no matter what fert I use. The other trees are not affected so obviously the fert is OK.
Dry or cold would be the only things I think would do that to Chinese elm but why only the elm I'm not sure.

 

[Bonsai Nut]

I've had similar problems with small/young Chinese elms when I defoliate them - even without fertilizer. They push a second flush of growth... and suddenly leaves start dropping. Initially I thought it might be a pest - a bird or something eating the new growth early in the morning. Now I think it might be fungus related, but I'm not sure. Wish I had an answer other than I still experience it (with some of my small cutting-grown stock) and I have no solution yet. Seems related to wet foliage and humidity, which is why I am leaning towards fungus, though the leaves that drop show no signs - they appear perfectly healthy. Good news is that it doesn't appear fatal - I have yet to lose a tree from it. Though it does cause me grief when trying to develop ramification - the trees are left looking sparse and spindly.

Note that I have not seen the same thing on my winged elms or American elms. Only Chinese elms.

 

[penumbra]

If you are fertilizing in Jan/Feb you may be attempting to grow your tree inside. If it is outside, there is no reason to fertilize as plant is dormant.

 

[sorce]

It's possible it doesn't have enough room in the pot too.

Also, the buildup on the basket is telling of meh conditions.

Sorce

 

[Toshi]

I can't imagine that it has anything to do with fertilizing even if you're applying a little too much. But I don't have any other idea what it may be either. I've neglected some elms and done terrible things to others, but they only defoliate come winter. Are they living outside, getting good sun?

It gets full sun on my balcony in spring and summer and comes inside when temperatures start dipping, usually around October.

 

[Toshi]

It's possible it doesn't have enough room in the pot too.

Also, the buildup on the basket is telling of meh conditions.

Sorce

That's dedinitely possible. I've had that basket for years so now i can't tell if it's just dirty or if that's salt accumulation

 

[Ben in Kzoo]

Why not leaving the tree outside when temperatures dip? these guys need dormancy

 

[penumbra]

If you tree spends all the several months of winter inside, it is remarkable that it is still alive.
Leave it outside so it can have a dormancy period. You can fool these elms for awhile, but eventually you will lose.

 

[MMJNICE]

My biggest mistake that I've had with Chinese elms was over watering that leads to root rot and fungal infections.. when they get fungal infections they are left wide open to Spider mites then the tree will drop all it's leaves... the mites will finish off your precious tree in weeks...

 

[MMJNICE]

Oh yeah what Penumbra said is true true true!! They can go about two to three years without an dormancy period before you start to see them slowly die.. this year will be the first year giving my 15+ years old Chinese elm dormancy in 3 years.. it has been pretty sickly it's last 2 years fighting fungal infections and spider mites no doubt because it hasn't had it's dormancy period in years.. I've come to realize that these elms are NOT inside bonsai. Ever since I put the elm I've been taking about outside it's health improvement was almost Immediate... it's been shooting new growth with vigor I haven't seen since I brought him home 4 years ago.. anyway good luck and if there is any chance you can give your elm fresh air and a chance to feel the Seasons change I can almost guarantee you will see an improvement.. and if you haven't already let your tap water sit for at least 3 days or so before watering your plants.. that just gives a little time for all the Chemicals to evaporate..

 

[Toshi]

Oh yeah what Penumbra said is true true true!! They can go about two to three years without an dormancy period before you start to see them slowly die.. this year will be the first year giving my 15+ years old Chinese elm dormancy in 3 years.. it has been pretty sickly it's last 2 years fighting fungal infections and spider mites no doubt because it hasn't had it's dormancy period in years.. I've come to realize that these elms are NOT inside bonsai. Ever since I put the elm I've been taking about outside it's health improvement was almost Immediate... it's been shooting new growth with vigor I haven't seen since I brought him home 4 years ago.. anyway good luck and if there is any chance you can give your elm fresh air and a chance to feel the Seasons change I can almost guarantee you will see an improvement.. and if you haven't already let your tap water sit for at least 3 days or so before watering your plants.. that just gives a little time for all the Chemicals to evaporate..

I plan to begin leaving outdoors permanently after next spring. In its current weakened state I'm not sure it'll survive the winter. I'll feel more confident once I can get this defoliation issue sorted first. I've transitioned to a controlled release 13-13-13 fert for now, I'm not even going to bother trying liquid feeding anytime soon.

 

[penumbra]

I plan to begin leaving outdoors permanently after next spring. In its current weakened state I'm not sure it'll survive the winter. I'll feel more confident once I can get this defoliation issue sorted first. I've transitioned to a controlled release 13-13-13 fert for now, I'm not even going to bother trying liquid feeding anytime soon.

I will be surprised if it makes it through another winter inside. It should be out now regaining its vigor.

 

[Toshi]

I will be surprised if it makes it through another winter inside. It should be out now regaining its vigor.

Sorry I think I misspoke somewhere, it's been outside on my balcony since April.

 

[Deep Sea Diver]

Gosh, maybe it’s the wintering over inside the house, the water, but now this situation sure sounds an awful lot like a really weak root issue. I had something this happen to one of my Chinese Elms and it went slowly downhill. RIP now.

It appears, from your description, even though you cut down on the strength of the fertilizer, the roots just couldn’t handle the slight osmotic shock the fertilizer provided and dropped the leaves. Those fleshy roots of the elm have a big surface area, so bad conditions in the media, accumulated over time can easily degrade the roots. At that point all it would take is something to toss off the tenuous hold on life the roots have to cause the tree to toss the leaves.

Some things I’d do.

1. Stop this fertilizer routine completely even if the tree recovers… at least for this year. If the tree leafs out, use something fairly innocuous (but smelly) like dilute at first fish emulsion, later maybe add Biogold if things improve more.
2. Do minimal watering / chock up on side of the pot a bit to promote more drainage.
3. Include 3 TBSP 3% H2O2 / QT water for a couple weeks.

Personally I wouldn’t check out the roots and media for now as if the elm roots are just hanging on, it might damage them further. (But you could.) Maybe once things are going well it would be time for a look see.

If the tree recovers, there’s no reason not to leave it outside, protected from the wind/full sun of course.

My take.

cheers
DSD sends

 

[leatherback]

It looks like your roots are just struggling to keep water coming. I personally dislike these pondbaskets as they dry out very fast. Add fertilizer and you have a reverse osmosis problem in your roots.

Do you have the option to put the pnd basket in a bigger pot and fill the gap with substrate? That would enourmously stabilize the rootclimate. (In my garden I would repot, but I have more trees than I can handle, so am willing to take a more risky approach)

 

[Toshi]

Gosh, maybe it’s the wintering over inside the house, the water, but now this situation sure sounds an awful lot like a really weak root issue. I had something this happen to one of my Chinese Elms and it went slowly downhill. RIP now.

It appears, from your description, even though you cut down on the strength of the fertilizer, the roots just couldn’t handle the slight osmotic shock the fertilizer provided and dropped the leaves. Those fleshy roots of the elm have a big surface area, so bad conditions in the media, accumulated over time can easily degrade the roots. At that point all it would take is something to toss off the tenuous hold on life the roots have to cause the tree to toss the leaves.

Some things I’d do.

1. Stop this fertilizer routine completely even if the tree recovers… at least for this year. If the tree leafs out, use something fairly innocuous (but smelly) like dilute at first fish emulsion, later maybe add Biogold if things improve more.
2. Do minimal watering / chock up on side of the pot a bit to promote more drainage.
3. Include 3 TBSP 3% H2O2 / QT water for a couple weeks.

Personally I wouldn’t check out the roots and media for now as if the elm roots are just hanging on, it might damage them further. (But you could.) Maybe once things are going well it would be time for a look see.

If the tree recovers, there’s no reason not to leave it outside, protected from the wind/full sun of course.

My take.

cheers
DSD sends

Thank you. Is that peroxide you mention? H2o2?

 

[Toshi]

It looks like your roots are just struggling to keep water coming. I personally dislike these pondbaskets as they dry out very fast. Add fertilizer and you have a reverse osmosis problem in your roots.

Do you have the option to put the pnd basket in a bigger pot and fill the gap with substrate? That would enourmously stabilize the rootclimate. (In my garden I would repot, but I have more trees than I can handle, so am willing to take a more risky approach)

After thinking about it I just realized that every tree that I've ever had in this cut down pond basket has died so clearly I'm not a suitable pond basket caregiver

I don't have any other pots unfortunately at the moment but may have to go out and get one.