Cam
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Posts: 2
Joined: Mon Aug 20, 2007 8:56 pm
Location: Wales, U.K.

New Zelkova: Mold problem

Hi,

My partner bought me my first bonsai, a Zelkova, 3 days ago :D . I read the provided guide and it said that if the soil appeared dry then to immerse the pot in a bowl of water until the air bubbles subsided.

I did this on the day of purchase because it looked and felt very dry. This morning I noticed white, cottonwool-like mold growing over the soil and the base of the tree :shock: .

I've searched other posts in this forum, sorry if I've missed some advice, I guess I'm panicking a bit :oops: . I would really appreciate any advice you could give.

Thanks in advance, Cam.

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Gnome
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Joined: Wed Jul 05, 2006 4:17 am
Location: Western PA USDA Zone 6A

Welcome to the Helpful Gardener.
I read the provided guide and it said that if the soil appeared dry then to immerse the pot in a bowl of water until the air bubbles subsided.
Please read the sticky about general growing tips, there is advice for watering there. Also follow the appropriate links therein.

Watering by immersion is not generally considered the best method especially in your climate, it might be different if you were in an arid location. I feel that there must be something else going on though. One time with this should not cause the mold problem if other factors are correct.

Where are you keeping it? outside with good air circulation I hope. Does it appear to be healthy otherwise? Can you please describe the nature of the soil, is it coarse and gritty of finely textured and organic?

Make sure that you allow the soil to dry sufficiently before you water it again. A picture may help as well, make sure to include a shot of the soil.

Norm

Cam
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Posts: 2
Joined: Mon Aug 20, 2007 8:56 pm
Location: Wales, U.K.

Hi Gnome, thanks for the welcome and the reply. Sorry for the delay in my response I've had to recharge my camera batteries :roll: .

I've been reading through the stickies and the links provided, also my Bonsai book has arrived in the post which has helped somewhat.

I've noticed that the mold has decreased slightly, there is none on the trunk anymore although there is a white residue left behind.

Attached are some pictures:

[img]https://i227.photobucket.com/albums/dd151/Cam-Pastime/Zelkova.jpg[/img]
Front view, overall

[img]https://i227.photobucket.com/albums/dd151/Cam-Pastime/FrontSoilRoot2.jpg[/img]
Front view, soil and roots

[img]https://i227.photobucket.com/albums/dd151/Cam-Pastime/BackSoilRoot2.jpg[/img]
Back view, soil and roots
Where are you keeping it? outside with good air circulation I hope. Does it appear to be healthy otherwise?
I've had it indoors in an attic conversion room, on top of a bookcase. It's a well ventilated room with dual window aspect. However, after reading through the stickies and my book I realise that even though the label says "indoor plant", I should probably keep it outdoors.

Apart from the mold problem it looks in good health. The leaves are green and there a new leaves coming through. I think it might need repotting. A part in my book says that signs that trees need repotting include "roots that appear like a coconut-fibre mat", which I think is apparent in the left hand side of the first two photos (right hand side in the third)?

The soil quality is currently slightly gritty on top, but under that it's like normal soil. I've got some Bonsai Compost to use for repotting if you think this would be okay? The soil has remained damp, even on the surface, since it's initial immersion, so I haven't watered the soil. Should I still spray the leaves?

Sorry for the essay, I hope the pictures help.

Cam

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Gnome
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Posts: 5122
Joined: Wed Jul 05, 2006 4:17 am
Location: Western PA USDA Zone 6A

Cam,

Thanks for the pictures, they do help a bit. I think it is a distinct possibility that you actually have a Chinese Elm. They are often confused with Zelkova, sometimes deliberately so. Compare the two side by side, the shoot on the left is a Zelkova, on the right is a Chinese Elm.
[url=https://img255.imageshack.us/my.php?image=zelelmzz6.jpg][img]https://img255.imageshack.us/img255/2258/zelelmzz6.th.jpg[/img][/url]
I've noticed that the mold has decreased slightly, there is none on the trunk anymore although there is a white residue left behind.--The soil has remained damp, even on the surface, since it's initial immersion, so I haven't watered the soil. Should I still spray the leaves?
Resist the urge to water until the "dampness has lessened" I have never bothered to mist my Chinese Elms, in fact this may cause problems by promoting "Black Spot" fungus, particularly on new growth.
A part in my book says that signs that trees need repotting include "roots that appear like a coconut-fibre mat", which I think is apparent in the left hand side of the first two photos (right hand side in the third)?
I think that the author may be attempting to describe a root-bound situation. The fibers that you pointed out are not roots.
I've had it indoors in an attic conversion room, on top of a bookcase. It's a well ventilated room with dual window aspect. However, after reading through the stickies and my book I realise that even though the label says "indoor plant", I should probably keep it outdoors.
I keep all of my trees outside with the exception of tender plants that come inside for the winter. If this is a Chinese Elm (sub-tropical) some growers do keep them inside over the winter. I prefer to allow mine to go dormant over the winter. If you are able to find a spot outside that gets some sun and some shade. The shade of larger tree would be ideal. Gradually, after you ensure that the tree has survived its recent trauma, it can be move to a brighter location.
The soil quality is currently slightly gritty on top, but under that it's like normal soil. I've got some Bonsai Compost to use for repotting if you think this would be okay?
I don't like the looks of the soil at all. Most deciduous trees are best re-potted in the spring. If it is a Zelkova this is the way I would go. If it is a Chinese Elm there is another option. As I mentioned some growers keep them inside for the winter, if you intend to follow this method it is possible to allow the tree to go dormant in the fall and then re-pot before bringing it inside for its "false spring".

I hesitate to suggest that you take this approach because we have not definitively identified it and because of your inexperience with bonsai. On the other hand you will need to re-pot it eventually, next spring at the latest. Can you post a picture of the bonsai soil that you have on hand. Be aware that even if it is suitable it will most likely need to be screened to remove the fines. I use a 1/8" screen to remove the smaller particles.

Norm

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