Repeated leaf drop

[ilithian]

Hey everyone,
I've had a chinese elm for a couple of years now(it was my first tree). And I'll admit its not had the easiest time while i've been learning how to look after it, I kept it indoors for about a year, but it's now been outside for over a year and all through winter. Anyhow, this year i'd thought i'd got it's care pretty worked out, but perhaps not..

It keeps dropping about 3/4 of its leaves and then a few weeks later it has a flush of new growth before a week or two later dropping them again. the leaves dont turn yellow or show any signs of bad health.. They just drop. It's just happening now for the 3rd time this year.

I don't think i over/under water, just when it's dry and needs it.

Does anyone have any ideas what might cause this? Could i be over feeding? Or does this sound like a watering problem? I cant see any other signs of disease..

Any help would be great, i'd hate to lose this tree!
Thanks,
Tom

 

[Poink88]

Tom,

Can you post closeup pics of the branches and leaves? Given your input, I am suspecting sucking insects. Look hard for any sign of them.

 

[ilithian]

I'll get some pictures when i get home tonight. I've not been able to spot anything before.. but maybe I'm missing something.
Thanks for the quick reply!

 

[coh]

I had a tiny little cotoneaster a few years ago that displayed similar symptoms...the only difference is that the leaves turned yellow or red before dropping. I thought about unpotting to check the roots but kept putting it off. Then one day a whole lower branch started to turn black and die...by that point it was too late. When I got it out of the pot I found the roots had rotted.

This was a mame plant in a small pot and I think the pot wasn't draining well because of low spots that held water. If I'd checked it sooner I might still have the plant. It had a nice little shape to it.

Anyway, just an observation. A photo and description of the type of soil might be helpful. If there are no insects you could try a fungicide, if that doesn't help a root examination might be in order.

Chris

 

[ilithian]

I hope these help. As you can see the leaves tend to drop near the start of each branch, the end leaves generally dont fall.
After looking really closely i did find some white residue/creatures? Could they be the problem? I can try and get more pictures of specific things if that helps.
Thanks for any help! I realise it's not the most exciting of trees, but i've come quite attached to it!
Tom

 

[coh]

Those white things in the first photo look like insect eggs but I can't tell what type. Could be good or bad.

I'm no expert on elms, as I only have one. But I can say (1) I've never seen mine drop leaves that are mostly green. When I get leaf drop the leaves turn yellow first (2) Many of the leaves on your tree, especially the newer ones, look a bit yellowish (some of the ones that dropped do also). This could indicate a root problem or nutrient deficiency. Hopefully someone with more elm experience can offer some solutions.

Some other questions that might help - what kind of exposure (how much sun) does the plant get? When was it last repotted? What kind of fertilizer do you use, how much and how often?

Have you done the spider mite test? Hold a white sheet of paper under the leaves and tap/shake them. If you have mites, some will fall onto the paper and should be (barely) visible as tiny moving specks. You can see them on the leaves (usually underside) if you know what to look for. Any fine webbing on the leaves, branches, tips?

Chris

 

[ilithian]

Those white things in the first photo look like insect eggs but I can't tell what type. Could be good or bad.

I'm no expert on elms, as I only have one. But I can say (1) I've never seen mine drop leaves that are mostly green. When I get leaf drop the leaves turn yellow first (2) Many of the leaves on your tree, especially the newer ones, look a bit yellowish (some of the ones that dropped do also). This could indicate a root problem or nutrient deficiency. Hopefully someone with more elm experience can offer some solutions.

Some other questions that might help - what kind of exposure (how much sun) does the plant get? When was it last repotted? What kind of fertilizer do you use, how much and how often?

Have you done the spider mite test? Hold a white sheet of paper under the leaves and tap/shake them. If you have mites, some will fall onto the paper and should be (barely) visible as tiny moving specks. You can see them on the leaves (usually underside) if you know what to look for. Any fine webbing on the leaves, branches, tips?

Chris

Thanks for all this, Chris.

As for your questions.. It should be getting plenty of light, mostly indirect. I did a half re-pot last spring to change it's pot, though it wasnt a full bare root repot. I alternate the feeding between a chemical and an organic one, and apply one or the other every two weeks-ish. I'll try the paper test tomorrow... I can't see any webbing anywhere though..
Hope that can help figure it out!
Tom

 

[ilithian]

I tried the paper test that Chris suggested.. and there were about 5 or 6 tiny yellowish creatures crawling around.. i tried to get a picture but they just come out as dots. I can try again if an ID is needed.. but i'm guessing i've got the dreaded spider mites?

Help! How can i get rid of them? Will they be on my other bonsai that this one has been close too? And any other plant?
Tom

 

[october]

Hello ilithian When you say it gets mostly indirect light. What does that mean exactly? Chinese Elms need full sun. This tree should be getting at least 6 hours plus of full sun a day. If your climate is not extremely hot, it proabably should be in close to all day sun.

Also, you mentioned you had it out side in winter. Certain elms, the ones with smooth bark, from southern china, should not be exposed to full winter conditions. Although a cold period is good for their health. Many times, some of these elms are treated like a sub tropical/tropical trees. Many bonsai nurseries keep them in heated greenhouses for the winter.

Rob

 

[bougie nights]

Looking at your first pic, I also saw what appeared to be eggs. Additionally, it looks like aphids or some other insect are on the stem and feeding. If they are in fact pests, they may be causing the problem, or they may be taking advantage of an already weakened tree.
You may want to try blasting them off with a stream of water.

 

[ilithian]

Hey, thanks for replying.
Uhm, Well i've been keeping it in a greenhouse. It was in full sun but since the leaf drop i moved it further back in case it was getting burnt(as unlikely as that is in the UK...). Is there a way to tell if this is a tropical elm? It was kept in the greenhouse over winter, so it shouldnt have got too cold i think?

I'll try hosing it all down tonight.. Is it worth spraying with an insecticide? I read somewhere about removing all the leaves to get rid of any eggs.. is that a good idea?
Tom

 

[coh]

A couple of thoughts...

1. Best to hose off the foliage early enough in the day so that it dries by nightfall.

2. I wouldn't remove the leaves. If you're diligent about spraying the foliage you should be able keep the mite population under control (as new ones hatch, the water dislodges them). Many plants can handle a small mite population without too many issues. I'm pretty sure that large scale growers (orchards, for example), won't spray until the "mite load" exceeds a certain level. I have a number of bonsai and pre-bonsai that have a "few" mites but natural predators seem to keep them in control. Since your plant seems to be suffering, it's probably worth treating, either with the water spray (if you want to avoid chemicals) or with a pesticide.

3. Similarly, if you choose a pesticide - you'll just have to re-apply at the specified interval to catch the mites as they hatch, as the pesticide probably won't destroy the eggs.

Chris

 

[ilithian]

Thanks, I gave it a spray down with water this morning and will keep repeating every other day or so i guess. Fingers crossed..! Might use a pesticide in between the sprays too.. i'll see how the water spraying goes.
Tom