Ulmus Parvifolia dying?

[OJavali]

Hey guys. So I bought this Chinese Elm 3 years ago. The bastard has been through some rough times, like the year I didn't realize it CANNOT BE INSIDE, and since then I've kept it in my balcony (-4º C to ~37ºC yearly temp variation). It started to develop a big amount of leaves, and even moss started to come, and it looks rather good (at least to my eyes), but even so, the tree is not uniform and near the trunk there is a weird colour appearing. Is my bonsai dying?

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EDIT: I need to do some pruning, but I turn the tree on a regular basis.

 

[Vin]

It looks like you have moss growing on the trunk as well as on top of the soil. First thing you need to do is get the moss off the trunk and then I'd also hit it with some fungicide. As far as weather it's dying or not, it doesn't appear to be. Mine do the same thing this time of year.

 

[OJavali]

It looks like you have moss growing on the trunk as well as on top of the soil. First thing you need to do is get the moss off the trunk and then I'd also hit it with some fungicide. As far as weather it's dying or not, it doesn't appear to be. Mine do the same thing this time of year.

The thing is, it's been like this for months. Including that light brown thing on the bottom of the trunk. How dangerous is it to have moss on the trunk itself?

 

[Vin]

I don't see a light brown thing on the bottom of the trunk. What I do see is black fungus or possible even canker around the base. Some trees handle moss on their trunk better than others. Generally speaking, the practice is to not let moss grow on the trunk. Among other things, moss will hold excessive moisture and promote fungus growth.

 

[OJavali]

I don't see a light brown thing on the bottom of the trunk. What I do see is black fungus or possible even canker around the base. Some trees handle moss on their trunk better than others. Generally speaking, the practice is to not let moss grow on the trunk. Among other things, moss will hold excessive moisture and promote fungus growth.

The light brown part is probably what you called the canker, underneath the black fungus thing. So, for now I should clear the moss from the trunk and apply some fungicide on the base of it? I also have some spider webs on the leaves. As far as causes, it's likely humidity or excess watering, right?

 

[Vin]

Yes, clear the moss. Apply fungicide and Insecticide to the entire tree. We have something here in the states called Fertilome Triple Action. It's a fungicide, insecticide and miticide. I've had good experiences with it but applying them separately from different suppliers is fine as well. Humidity is probably not the cause. Over watering and Mother Nature are more likely the culprits. BTW, a spider and web on your tree is not necessarily a bad thing, spider mites are (bad).

 

[OJavali]

Alright, will do. Thanks for the advice, I think I will try and find the triple action product, although I might already have it. Do spider and spider mite webs look different? Although there isn't that much web I think I'll keep my eyes open for it.

 

[Bonsai Nut]

The thing is, it's been like this for months. Including that light brown thing on the bottom of the trunk. How dangerous is it to have moss on the trunk itself?

I am concerned about this tree. The growth is leggy and weak. I would also be worried about the wound on the trunk. Looking at the photo closely, it almost appears that the tree is pushing roots at that location, which could indicate that the tree has been injured, or in some other way the vascular system has been compromised. Doesn't look like fungus to me, but hard to say - just that something is bothering this tree greatly.

When is the last time you repotted and checked the roots?

 

[OJavali]

I am concerned about this tree. The growth is leggy and weak. I would also be worried about the wound on the trunk. Looking at the photo closely, it almost appears that the tree is pushing roots at that location, which could indicate that the tree has been injured, or in some other way the vascular system has been compromised. Doesn't look like fungus to me, but hard to say - just that something is bothering this tree greatly.

When is the last time you repotted and checked the roots?

Since I acquired it in 2013 it has never been repotted. I have been to a place where you can buy plants and I was told at the time that there would be no necessity of doing so for some time, but that was last summer. Upon closer inspection I can remove the tree and the soil in 1 piece and the roots have yet to be checked.

Could they be rotting? Could a repot and possible root prune help?

EDIT:
After another inspection I saw fine roots near the edge of the pot, which did not look black, but a light brown color, along with a 1-2 mm spider running through the soil, and a yellow ball, 3 mm in diameter.

 

[markyscott]

The moss and weak growth are both likely symptoms of the waterlogged conditions this tree is growing in.

Scott

 

[OJavali]

The moss and weak growth are both likely symptoms of the waterlogged conditions this tree is growing in.

Scott

So maybe let the ground dry up a bit, and maintain some of the moisture, but less? Would repotting help?

 

[markyscott]

If it were mine, I would definitely repot this tree in spring. Looks like your zone 9 in Portugal - you can do it in Jan/Feb. For now, you might clean up the top soil. Do you know how to do this?

Scott

 

[OJavali]

It's definitely a very hardy tree, and can definitely take a beating. That's great to know, I thought Spring maintenance was around early March. But I also thought it could be done during Fall. I never even knew the top soil could be cleaned! Can you spare some tips? My gardening knowledge is limited, but I guess we're only limited by our will! Oh, and this is my first bonsai ever, so it's very dear to me and I'll do what I can to help this little fellow

 

[markyscott]

It's definitely a very hardy tree, and can definitely take a beating. That's great to know, I thought Spring maintenance was around early March. But I also thought it could be done during Fall. I never even knew the top soil could be cleaned! Can you spare some tips? My gardening knowledge is limited, but I guess we're only limited by our will! Oh, and this is my first bonsai ever, so it's very dear to me and I'll do what I can to help this little fellow

Have a look at this post - in it I describe how to clean up the top soil. You can do that now and it will help. Then start thinking about repotting in early spring. You can do it anytime during dormancy in your area - I'm guessing that you have almost no danger of a hard freeze.

Scott

 

[OJavali]

Great post, very insightful and easy to follow! So, cleaning the top soil is meant to straighten out the roots as well as renew the nutrients that are on the top? In a smaller, rectangular pot could I end up damaging roots, or will this be actually very healthy for them? I noticed you have a square and a wooden slab underneath.

 

[markyscott]

Great post, very insightful and easy to follow! So, cleaning the top soil is meant to straighten out the roots as well as renew the nutrients that are on the top? In a smaller, rectangular pot could I end up damaging roots, or will this be actually very healthy for them? I noticed you have a square and a wooden slab underneath.

Just remove the top 1/2"of the soil. All the moss, left over fertilizer, compacted and degraded soil, and whatever else is up there. Do it with a pair of bent-nose tweezers as I did in the post by drawing the tweezers away from the trunk and toward the edge of the pot. You'll naturally damage crossing roots and leave the radial ones alone, but that's not the point of the exercise for you - you're just trying to refresh the top soil. Replace it with a granular, well-draining mixture and wait until Jan/Feb to bare-root repot completely.

Scott

 

[OJavali]

Thanks a lot for the help Scott! Can you please explain why it wouldn't be a good idea to repot now? Also, I should repot to a bigger pot, correct?

 

[Zach Smith]

Hey guys. So I bought this Chinese Elm 3 years ago. The bastard has been through some rough times, like the year I didn't realize it CANNOT BE INSIDE, and since then I've kept it in my balcony (-4º C to ~37ºC yearly temp variation). It started to develop a big amount of leaves, and even moss started to come, and it looks rather good (at least to my eyes), but even so, the tree is not uniform and near the trunk there is a weird colour appearing. Is my bonsai dying?

EDIT: I need to do some pruning, but I turn the tree on a regular basis.

Your soil looks mucky, from what I can see. The tree needs to be repotted into fresh, well-draining soil. This is almost certainly the cause of your problems.

Zach

 

[OJavali]

Your soil looks mucky, from what I can see. The tree needs to be repotted into fresh, well-draining soil. This is almost certainly the cause of your problems.

Zach

But when can I do it? Should I do as Scott said and renew top soil first?

 

[markyscott]

Thanks a lot for the help Scott! Can you please explain why it wouldn't be a good idea to repot now? Also, I should repot to a bigger pot, correct?

Hi OJavali. As a rule, I never advise fall repotting unless there is really no other choice. Here's a nice blog entry on the subject from Michael Hagedorn.

https://crataegus.com/2016/09/03/confusion-over-fall-repotting/

Your tree is not in imminent danger of dying, January is only a few months away, and I don't have a good idea of your experience level. So, in my opinion it's not worth the risk and I'd advise just changing out the topsoil to improve drainage in the near term and save the major repotting for when it's safest to do so.

Scott