Failed repotting of japanese maple

[BalconyBonsai]

Hi, I have just gone through my first repotting season as a bonsai enthousiast and it has been a mixed bag. Unfortunately on the minus side was my favorite tree, a big japanese maple that I found, what I think was really cheaply(compared to other trees of similar size). Anyway, it was planted in a pot that turned out to not be frost proof and since we had some really cold weather this winter, it cracked big time, literally broke into pieces. I ordered a new pot that was a couple of sizes larger but I misjudged the depth that would be needed. But this I notice on the day of the repot, when I already removed the tree from the old broken pot having struggled with pruning the roots being planted in really hard clay like soil, and then seeing it is way to high for the new pot. I did not want to remove any more of the soil/root mass under the tree for fear of disturbing the tree any more. I had no other pot of a big enough size so I had to go through with using the new shallow one. The old pots was split in 4-5 pieces. Anyway, the tree now sits really high and I need to continously add new soil to replace soil that has been washed away when watering. I am trying to water as carefully as possible but the slope of the soil makes it very difficult.

The repot was to be done this spring by suggestion from the store from which I bought it. Some of its buds had just started to extend and reading guides about finding the correct time to do repotting, this meant it was time. I did the repot like 2 weeks ago and it is still continuing to push out leaves, no full lead yet but we have had a week of quite cold weather again so many trees also in nature have not gone in to leaf yet.

So my question is, should/could I repot this again into something deeper to try and save this failed repot or should I just wait it out and hope for the best and tey again next year? I can't see any signs of the tree being unhappy at the moment but like you see in the screenshot, it looks almost like the old rootmass is just placed on top of the new soil, not in the new soil if that makes any sense. It really looks horrible and I'm ashamed of posting this image but I really would like to learn and give the tree the best chance it's got.

Thanks

 

[Cadillactaste]

I would use plastic from a milk jug or something similar...and insert it on the inside of the pot and raise the lip that way...and fill it with soil. I would not leave it as such. Assuming tree is in leaf now.

 

[Pj86]

I second Cadillactaste recommendation if has already fully leafed out. If it is still in bud, I would change the pot but avoid working the roots as much depending on how strong the growth was the prior year.

 

[Shibui]

It may just be the camera angle but that looks like a very thick trunk in a very small pot. Bonsai is not about getting a tree into the smallest possible pot. It should be a balance between what looks good and what it good for the tree in a horticultural sense. I know I would have an uphill battle to keep a JM healthy in suchc a small pot over summer here.
If the leaves were not too advanced I would consider a second root prune but it might just be a little too much to get this tree into this shallow pot.

There should be no problem just transferring it into a larger pot provided you are gentle to minimize the number of new roots that break. Most trees are easily able to replace a few new roots, even after a previous major root reduction. It is not necessary to use a chopstick to force soil into the rootball this time round. Doing that would cause far more damage. Soil will move into most spaces when you water in and a few air pockets does not actually cause problems - the soil we use for bonsai is specially designed to have lots of air pockets, a few slightly larger air packets won't hurt the roots.

I concur with the previous advice to build a wall round the rim of the pot to retain enough soil to cover the roots as a viable option.

 

[Deep Sea Diver]

Concur with @Shibui, slip potting the Maple into a bigger, deeper pot would be highly preferable. Given you use the very same media and after potting care, absolutely no damage should be done... Just easy goes it during the transfer.

Other options, build a grow box, or go thrifty and use a nice sized Anderson flat, which I would do if there is one in had..

I think building a wall around a pot could be a long term headache unless you use the correct material, which would bea flat expanded metal mesh. See this link for a what I’m referring to...

btw you aren’t the first, nor will be the last person to make the same mistake. Given you take speedy action, things will be fine.
cheers
DSD sends

 

[LeoMame]

I have been there myself too, and what I did was to simply buy a plastic training pot, large enough to host the rootball comfortably, then slip it in without messing up with the roots anymore. This can be done even if the tree just leafed out, as I did: of course you gotta prepare the pot and the soil very carefully and do the operation with properly and quickly.

Next year you will have more time and experience to better repot your maple into a bonsai pot of your taste, now it feels it's more about an emergency slip pot, so the health of the tree comes first I suppose.

I have learned a lot from the feeling of being unhappy with a wrong angle at repotting, or poor pruning and such. This is bonsai, this is the learning process for me

 

[Cadillactaste]

Honestly...I can't see the tree thriving if left as is. Slip potting and not messing with the roots...and use the same substrate medium to finish filling the pot would be the best bet. Those roots are so vulnerable.

 

[BalconyBonsai]

Thanks everyone for your suggestions and advice! It has not leafed out yet, some branches has leaves that have come out but they are still folded up, the other ones are still in the bud phase. I now have a much deeper round training pot, about the same size in diameter so I will make an attempt at slip potting it to that one. I take it that is the preferred solution if the tree is not in full leaf? Since this would be a much deeper pot, like a "normal" plant pot, is there a danger of putting too much soil in there? The pot it came from initially was about 8 cm high, maybe 6,5 cm deep on the inside. This new one I'm thinking of moving it to is probably around 25 cm on the inside. I'm just thinking if planting it in too deep soil will cause issues when replanting it in a bonsai pot in the future? I guess I could simulate the soil depth of a bonsai pot and just not fill out the pot completely but then the tree will sit very low in the pot which also might not be good...

Hopefully the tree will be alright.

 

[Deep Sea Diver]

Gosh, now it seems you are going to the opposite extreme...

First, the timing seems fine to repot.

Second, I’d suggest you plant the tree to the proper depth, with the container wall about 1.5 cm above the top of the roots. If it’s a training pot, it’s likely plastic. Cut it down. If not, just get something the correct depth, an Anderson pot would work fine. That will give you a year to find the right pot.

The issue is the the roots are going to want to occupy the entire container. Downward and around. That will waste another year or more of training time while it’s in the deep pot.

You should get the right pot for the job.

Good luck,
DSD sends

 

[Pitoon]

Get yourself a new pot, repot without touching the roots. There's a good chance those roots exposed will dry out and die if you leave it as is.

 

[BalconyBonsai]

Ok, I understand. I think I will need to go with the option of cutting down the training pot. Bonsai pots are not so easy to get hold of here, there will be at least 1 week of delivery time before I could get one here. And since I have not been doing bonsai for long I don't have a stock of pots laying around either.

 

[Mikecheck123]

Bonsai pots are not so easy to get hold of here

Why do you need one? Get a $1 5-gallon nursery pot from Home Depot.

 

[BalconyBonsai]

Why do you need one? Get a $1 5-gallon nursery pot from Home Depot.

That's basically what I have, but it is around 25 cm(10 inches) high, which I understood would be too high. So I wrote what I did about bonsai pots just to illustrate what my options are.

 

[BalconyBonsai]

Ok, job completed. Hopefully it will be happy in this even though it probably still was a bit deep after cutting the pot.

Thanks everyone who chimed in for your ideas and suggestions!

 

[Deep Sea Diver]

Looks good!

I’m not too sure about the drainage dish... I wouldn’t use it except for show. In that case bore a bunch of holes in the bottom of it.

cheers
DSD sends

 

[BalconyBonsai]

Thanks! The drainage dish is a compromise with my girlfriend so I can have it our wooden deck. We are a bit worried the water might damage it. When I water the tree I set the pot up between two bricks the let the excess water drain out. So the dish is only meant to stop the later moisture from leaking out on to the deck. What do think could be the problem with it? Drainage? The pot itself has 6 drainage holes at the bottom and 5 on the sides just at the bottom level.

 

[Paradox]

Thanks! The drainage dish is a compromise with my girlfriend so I can have it our wooden deck. We are a bit worried the water might damage it. When I water the tree I set the pot up between two bricks the let the excess water drain out. So the dish is only meant to stop the later moisture from leaking out on to the deck. What do think could be the problem with it? Drainage? The pot itself has 6 drainage holes at the bottom and 5 on the sides just at the bottom level.

Um does it not rain the deck? I had my trees on a wood deck for 10 years and it didnt do any more damage than the rain or, or 3 dogs and people walking on it every day.

 

[BalconyBonsai]

Um does it not rain the deck? I had my trees on a wood deck for 10 years and it didnt do any more damage than the rain or, or 3 dogs and people walking on it every day.

Our line of thinking is that small amounts of soil will be flushed out onto the deck everyday causing more damage than "just" rainwater. But we are very new deck owners having only had concrete patios before so we are not very knowledged when it comes to these things so we tend to err on the safe side. But good to know it's not a problem!

 

[Mikecheck123]

still was a bit deep

There's no such thing as too deep. A tall pot drains better than a short pot of the same diameter. If you're worried about downward growing roots, plant it on top of a tile or a piece of broken pottery.

That drainage dish doesn't look ideal. It will just cause water to pool in the bottom of the pot. If you're worried about deck damage I'd use something much larger, like a humidity tray, or even an aluminum foil baking pan. Basically you want the bottom of the pot to have access to air and not be saturated in water.

 

[LittleDingus]

Our line of thinking is that small amounts of soil will be flushed out onto the deck everyday causing more damage than "just" rainwater. But we are very new deck owners having only had concrete patios before so we are not very knowledged when it comes to these things so we tend to err on the safe side. But good to know it's not a problem!

I grow lots of trees on a deck. It really is more about staining than "damage". Dust and grime will even collect around your drainage dish and possibly discolor the deck depending on what collects, how damp it stays from rains, etc...



The picture's not great but can you tell where a pot used to be?

Drip trays won't completely eliminate this...but they do help.