Chinese Elm dropping leaves too soon


#1

Hi BonsaiTonight community,

I would like to share with you a couple of pics of my Chinese Elm, which drop the vast majority of its leaves in July and August, in order to know your thoughts and suggestions on the issue affecting this plant.

I own this plant since December and didn’t observe its full-year cycle yet.

After a vigorous growth in spring, since July the leaves look overall weak, some are yellow with a brown area nearby the petiole.
Suspecting a root-problem I took the tree out of the pot but, to my knowledge, everything looks fine.

I’ve also checked the tree for spider mites (white sheet test) with no results.

Here’s a list of the key info related to this plant:

  • local temperature: 82-89 F
  • location: covered in a bright place (not in full sun due to the hot temperature)
  • fertilizer: organic but interrupted in the beginning of July to avoid water loss from the roots in heat
  • soil: sand and organic compost
  • watering: every 2 days due to the deep pot and soil type
  • additional treatments: B12 spray once a week

Looking forward to receiving your suggestions.

Many thanks!
Cheers,
Leo


(Frank Corrigan) #2

Could you comment on your location and zone. My initial reaction based on the leaf coloration would be overwatering. Turning yellow from the petiole outwards. My own elms drop their leaves fairly early on in late September, early October. If they suffer from too little water then they show burned portions quickly on their outside leaf edges.
We have had a very warm summer as well with similar temperatures. My soil mix is inorganic with free drainage and i have used organic fertiliser as well as some 14-14-14 osmocote throughout the growing season beginning in mid april.
The elms get watering twice a day because i have a drier less retentive mix.
The difference i note in your description is soil mix, fertiliser application and possibly watering routine. Hope these comments help.


#3

Thank you a lot Frank,

The tree is located in Italy with a humid weather and temperatures ranging from 82-89F. I tend to exclude lack of watering due to the fact the tree is covered under a tent and, as you noticed, the soil is pretty retentive. I received it in that mix and I will switch to an inorganic mix as soon as possibile but not now.

In your experience with this specie, apart from paying attention to watering and under an overwatering scenario:

  • should the tree be placed in full sun or remain covered?
  • should I switch to misting the trunk and the remaining leaves instead of watering the roots (at least for few days)?

Your help is much appreciated!
Leo


(Frank Corrigan) #4

The tree in this condition should be in partial sun and shade protected from drying winds. I would start by soaking the tree and pot for fifteen minutes. immersing in a tub or large pot. Use a wooden chopstick to poke holes down through the root ball. This will allow more even watering and ventilation to the roots in case the centre portion of the root ball is compacted with old soil. Then allow the tree to dry out partially before watering again. Elms should be kept moist but not wet. If it continues to drop leaves then be sure to not overwater as the tree will be using less with fewer leaves.
I do not reccomend misting the trunk, misting the leaves is ok.


#5

Just a quick update on the tree.
Frank definitely nailed it! After having follwed his suggestion the tree is showing impressive vigor.
Thank you!


(Frank Corrigan) #6

Great to hear! When you repot, pay particular attention to the center core of the root ball. Remove all dead and decaying roots. All the compacted soil in the middle and reduce or remove downward major roots. Address that issue first from the bottom, then leave the majority of the healthy roots alone near the surface and outside for the next time you repot. Be careful to fill the cavity in the center with free draining and appropriate sized media. Leaving no vacant spaces. You should notice a big improvement again after the repot.
Best of luck.