Acer Palmatum Sango Kaku

[AndyJ]

Hi folks.

Sorry for another question about air layers!

I put an air layer on a landscape A.P. Sango Kaku earlier this spring using sphagnum moss and a bag (as I'm disabled I cant use the pot and bonsai compost process as I can't guarantee when I can water). After checking the roots this week, I'm disappointed to see that I've only got a couple of big white roots. The tree was subjected to full sun when we had the heat wave and most of the top growth is showing signs of damage - I'm guessing because the layer has interrupted the water flow up and down the branches? Maybe this has resulted in only a few roots growing?

I'm wondering whether it would be a good idea for me to take the plastic wrap off and put it in a pot with bonsai soil now? I am thinking that the new "tree" might push more roots out into the compost as we approach autumn? Then remove the layer later, maybe middle of September?

I know there is a risk of not having enough roots this year to support the new tree, so I thought about leaving the layer on over winter but as it's a landscape tree, will this work? It would mean the layer and new roots would be exposed to winters temperatures. Could it handle this?

Confused.....what would you do?

Andy

 

[AlainK]

Hi Andy,

I don't think it's the right time to mess with the roots.

Is the bag open at the top so rainwater can flow into the mix? The temperatures will eventually get cooler and rain will come before the end of the season. If the weather is not too harsh where you live, I would wait until next spring to severe the layer.

Let's see what the others say...

 

[AndyJ]

Thanks Alain.

I wasn't thinking of messing with the roots - I don't think I explained my thoughts too well!! I was meaning to remove the plastic wrapping and put it in a pot "as is" and just surround the moss ball with bonsai soil. Hoping the roots may grow out into the compost.

I live in Carlisle - NW England. While we don't get temperatures like our friends in the US and Canada do, we can get freezing temps around -5 to -10 on occasions as well as loads of rain and wind. Was wondering whether the layer would cope with this?

 

[AlainK]

If you proceed carefully, not breaking the white roots, and use a plastic pot, it could be OK.

Of course, the ideal thing would be a transparent container (big plastic bottles or sthg else) taht you then wrap in dark plastic. Then, when the leaves fall, you'll be able to see if there are roots around the container after lifting the black sheet of plastic. If there are enough, you can remove the layer, if not, wait until next spring.

 

[AndyJ]

Clear plastic?! That's a great idea, I'll see if I can find something big enough

 

[AlainK]

For example that's what I did on a small juniper. I had put a wire around where I wanted to layer it, but that's not really necessary, except that it enlarges the base a tad so there's hope of a better nebari.

Yours may be bigger, but that's the idea:

 

[Paulpash]

The layer's top foliage is at present supported by a dual root system - the original roots as well as the additional roots that you have in the bag. By cutting the ring of bark you interrupt the flow of nutrients back down to the roots but not the water supply up to the leaves. Hormones "pool" at the top of the upper cut you made and prompt the tree to form adventitious roots in the presence of moisture. This is why you will often see buds popping below the layer - the top is now not providing any nutrition and the tree essentially views this as a 'chop' and throws out more shoots below it.

If you remove the layer too early before enough root is formed in the bag you risk the top not being able to hydrate itself. The recommendation is therefore to leave the layer on for as long as is necessary to sustain the volume of foliage above it. Typically, when it's "full of root" is the best time to separate. Overwintering the layer in the event that not enough root is formed should not be a problem - the tree will dump its sugars into the new roots just as it would do normally in preparation for Winter.

 

[AndyJ]

Yes, that's my understanding Paul, however, my tree is showing signs of lack of something above the layer. The rest of the tree is nice and green (albeit with some top shoots burned by the sun) but everything above the layer is yellow, with a pinkish tinge. If it's not lacking water from the layer's cut, what else is going on?

 

[Paulpash]

Yes, that's my understanding Paul, however, my tree is showing signs of lack of something above the layer. The rest of the tree is nice and green (albeit with some top shoots burned by the sun) but everything above the layer is yellow, with a pinkish tinge. If it's not lacking water from the layer's cut, what else is going on?

From having done loads of these on various maples Inc Sangu Kaku I know from experience this means it's a good thing - it's working (obviously if they are brown & crispy no it isn't) . Often the leaves above an air layer colour a little bit - almost like the beginning of Autumn. The other clue like I said before is buds / shoots growing just underneath it. Maybe @0soyoung can provide a horticultural reason why leaves above an air layer have a slight colour change?

Nb: I have found Sangu kaku to not be as reliable as other maples when air layering - I think I'm 2/4 whereas other maples it's very high.

 

[Paulpash]

From having done loads of these on various maples Inc Sangu Kaku I know from experience this means it's a good thing - it's working (obviously if they are brown & crispy no it isn't) . Often the leaves above an air layer colour a little bit - almost like the beginning of Autumn. The other clue like I said before is buds / shoots growing just underneath it. Maybe @0soyoung can provide a horticultural reason why leaves above an air layer have a slight colour change?

Nb: I have found Sangu kaku to not be as reliable as other maples when air layering - I think I'm 2/4 whereas other maples such as Orange Dream, Kiyohime, Arakawa, Katsura etc it's very high.

 

[AlainK]

Paulpash good words wrote.

AndyJ Paulpash must hear.

 

[0soyoung]

Maybe @0soyoung can provide a horticultural reason why leaves above an air layer have a slight colour change?

So, because of Polar Auxin Transport (PAT) auxin piles up at the top of the girdle (where the cambium now ends). Excess auxin induces the production of an ethylene precursor ACC, some of which winds up in the xylem sap stream. At the leaves there is enough oxygen for an enzyme, ACS, to oxidize ACC releasing ethylene. Ethylene is what causes leaf senescence - so the leaves color to a degree similar to what they would in fall. Usually the natural effect with a layer is unnoticeable, but with some varieties it is (obviously).

For anyone that is interested, some educational fun can be had with this. One can get some very strong IBA powders from Hormex and make a real show of this. Just dust the stronger powders to get more coloration. Since more coloration means less photosynthesis, excessive IBA is not a good thing for producing layers, but even 4.5% IBA is not fatal, generally speaking.

 

[0soyoung]

an enzyme, ACS AC oxydase, to oxidize ACC

 

[AndyJ]

Thank you for clarifying Oso - I won't pretend to fully understand what you have written, but I can determine that leaf colouration above a layer is normal and, as PaulPash says, is a good thing!

 

[Paulpash]

Thank you for clarifying Oso - I won't pretend to fully understand what you have written, but I can determine that leaf colouration above a layer is normal and, as PaulPash says, is a good thing!

You live in a great part of the country Andy - I often go up there to Kielder Forest. For a guy mad on trees it's an amazing place!

 

[Kendo]

If in bag you can put a small aquarium size hose in to the bag and water from there. with some small root light feeding and water will provide nutrition for increase growth. You can pinch off hose and leave in bag secure.

 

[AndyJ]

You live in a great part of the country Andy - I often go up there to Kielder Forest. For a guy mad on trees it's an amazing place!

You're right Paul, it's great up here (when the weathers good!). I live about 45 minutes from Kielder, The Lake District and Dumfries and Galloway in Scotland! Lots of trees to see ??. Some great beaten up by the weather trees in The Lakes. I recall reading somewhere that you like it up at Kielder, do you get up there often?

 

[AndyJ]

I've had a look at this again today and there are definitely roots in there - cant see how many though, and not enough to support the top growth. I've tried something similar to what Alain suggested but as I'd already started the layer I've tweaked it by taking off the plastic wrap, putting on a clear pot filled with bonsai compost and then put a black plastic pot around all of it. Hopefully I'll get some root growth now that fills my clear pot with roots and I can separate in the next few weeks. If I don't get enough root growth, I'll leave it on until the spring.

 

[Paulpash]

You're right Paul, it's great up here (when the weathers good!). I live about 45 minutes from Kielder, The Lake District and Dumfries and Galloway in Scotland! Lots of trees to see ??. Some great beaten up by the weather trees in The Lakes. I recall reading somewhere that you like it up at Kielder, do you get up there often?

I'm going up there & the Lakes mid September time. This is coincidentally when my layers are usually ready (mid September /early October) if I start them in April. Keep an eye on them now every week for water - the roots tend to grow quite a bit faster from now on and will draw out more moisture as they colonise the bag. Are you good as regards aftercare mate?

 

[Paulpash]

I found a pic of some of the maples I took last year next season I'm air layering the air layers lol - each is about 5ft tall. All were originally taken from my stock tree which is now in a crate waiting to be trained.