Help! Overwatered maple?

[deanpwr]

I recently got an unwanted Japanese maple from a garden. I dug it up before the buds started swelling in spring. I heavily pruned and washed the roots. I potted it up in a holed basket (with lots of drainage holes on the bottom too) in pure attapulgite (cat litter). I placed lots of sphagnum moss in a layer around the roots to encourage root growth. Some weeks later the spring buds popped.



HOWEVER, as you can see below, the spring leaves are not doing so well...





Do you think it's overwatered or underwatered?

It could be underwatered as the roots were pruned so heavily, but I think it's more likely overwatered as attapulgite holds a lot of water even after it drains.

Yes I know potting it up in pure attapulgite was a bad idea.

What's the best thing to do at this point?

 

[Rivian]

If you think the leaves are hanging because transpiration exceeds water uptake, increase turgor by removing leaves.
Although it might be frost? You didnt say your climate.
Sure looks like Sangokaku btw

 

[deanpwr]

If you think the leaves are hanging because transpiration exceeds water uptake, increase turgor by removing leaves.
Although it might be frost? You didnt say your climate.
Sure looks like Sangokaku btw

Yeah one thing is the size of the tree is very disproportionate to the root system. The soil doesn't seem to be drying out too quickly though.

I don't think it's frost, I brought it in for a few frosty nights recently.

 

[Rivian]

The soil doesn't seem to be drying out too quickly though.

Trees can dry to a crisp while standing in damp soil if they dont have roots to drink.

 

[Firstflush]

Like others have said....maybe a frost or you removed a huge amount of roots and didn’t top prune enough I.e. the root mass water intake can’t keep up with the top growth. I’m no maple pro however.

 

[deanpwr]

Yeah I had to remove a lot of roots. I feel it may not have enough roots to support the foliage mass.
Question - if I remove branches/foliage, will the tree have enough in reserve to push roots without photosynthesis?

 

[Deep Sea Diver]

Hmm...

Here’s a Sango Kaku in pure NZ sphagnum that is soaking wet. It’s an airlayer with minimal roots. It’s kept in open sky, but only gets full sun for an hour or so in the early morning.



Your newly potted tree, likely with pruned roots from the looks of it, seems to be in an area with lots of direct sun. It’s no wonder the tree isn’t doing all that good, cat litter or not.

I’d take it out of the sun right quick. Also consider carefully getting that tree into something with a more open draining soil soonest.

Let us know how that works.

cheers
DSD sends

 

[sorce]

The things that concern me are the sphagnum, the possible heat in that nook, and the going inside.

Sorce

 

[Deep Sea Diver]

Yep, the airlayer will be potted on within a month or so.

The climate here is so moderate that we can usually repot late Feb - late Sep, barring Big Smoke events.

cheers
DSD sends

 

[SC1989]

Like sorce said, too much direct heat plus too much wet sphagnum. I failed a layer last year the same way

 

[deanpwr]

What's the issue with too much wet sphagnum? Would the insufficient root ball not be the issue here?

 

[HorseloverFat]

Did the repot/open-chest plant “surgery” happen when the tree was awake?

They don’t like that.. but they can survive with proper aftercare... no direct sun, no freezes or frosts, a clear, plastic bag over it to act as a “green-house suite”..

If it were my tree.. I’d “whack it back” more, but that’s just personal , get it in a bag and into the “bright shade”...

Kitty Litter?... so not U.S.

You could have to worry about volcanic ash or penguin damage for all we know.

 

[deanpwr]

Slightly later than I would have liked to dig it up, the buds had elongated and nothing would stop them from popping at that point when open chest surgery was performed.

Weather has been mixed, from 3-15 C with plenty of sun and rain (UK region).

BTW this tree has been in a front garden without shade for over 15 years, I doubt we get enough sun here for it to be a real problem!

 

[HorseloverFat]

Slightly later than I would have liked to dig it up, the buds had elongated and nothing would stop them from popping at that point when open chest surgery was performed.

Weather has been mixed, from 3-15 C with plenty of sun and rain (UK region).

BTW this tree has been in a front garden without shade for over 15 years, I doubt we get enough sun here for it to be a real problem!

It has to do with how plants behave after “root-disruption” more than that specific trees resiliency.

You broke and re-arranged the tree’s “straws”.. it has to learn to drink again and regrow those tiniest straws (roots), for THESE are where the tree takes up the most water..

While it is “recovering” and trying to regrow those tiny straws, and learn what roots it has left... you risk the foliage drying out.. taking the corresponding branches with it, and eventually drying the tree out BEFORE it’s “clutch” catches.

If you leave it in the sun... it’ll grow again.. but from lower buds.. and THOSE particular branches and foliage wont survive the “crispy overlap”

 

[HorseloverFat]

The sphagnum around the rootmass also concerns me.

A soaked “shin” will kill a tree... even tough trees... brought down a Ginnala I really liked.. I had repotted but left too much clay soil in the center of the rootball.

 

[Mikecheck123]

Balance is very important for all aspects of working on trees.

After you hacked away the roots this tree is about 50 times too tall.

I would cut it way back just above the first branch.

Luckily Sango kaku are extremely resilient, and it will probably survive if you give it a chance.

 

[leatherback]

Your problem is the sun and wind exposure.

You removed many roots. Maples can deal with that just fine if done at the right time (Which you have by the sound of it).

The sphagnum is not needed and is actually problematic. Remember we want the rootball to dry a little before watering again? You have now created a dense wet area around the root stumps, instead of a humid aerated environment. So the rootstumps have an easy life getting access to water and are not stimulated to penetrate the substrate further. The type of substrate does not help.

I see 2 routes:
One:
For now, move it into the shade & wind
Be carefull with watering
Leave it alone.

Two:
If you do not trust the substrate you have (Sounds like the same stuff I bought in spring and after a 24h water test, I tossed it because it became soft clay)
Defoliate, leave the growing tips and tiny leaves
Take out of the container, and gently tap-shake the substrate off. What clings, clings.
Pull off the sphagnum
Put in proper substrate

Put in the shade untill it starts pushing again.

Number two is a more fundamental approach, but with a risk: Any young roots that may have formed, will be severely damaged. It requires gentle, experienced hands. I would opt for it, as I do not trust your substrate to stay intact untill the next viable repotting moment.

Secret option three, do 1. In summer do 2.

Did you see this: https://www.bonsainut.com/threads/leatherbacks-deshojo-maple-renovation.49413/
This tree gets 2 hours of direct sun, right at sunrise. Once the sun is truely up it turns behind the shed. It sits in a corner between 2 sheds, so no wind there either. It is suffering the massive rootreduction I did there.

 

[deanpwr]

Thanks for the detailed reply.

I have seen experts plant yamadori in pure sphagnum moss for root growth, and also placing clumps of it around any thick pruned roots. They swear by it. I also doubt the moss would stay soaked as the litter would act like a dessicant. Still I have no proof of any of this first hand - this is my proof (wilt)!