airlayering

Hi, I have a simple question about air layering. how far do i cut into the bark do i cut? Do I cut just to the white part or all the way to the wood?
thanks, Zac

All the way to the wood and then a bit more. The layer under the bark and over the wood is the cambium and needs to be scraped away for a layer to work.

thanks kev.
Zac.

Personally I would be careful about going any further than the cambium. The water conducting vessels are in the wood directly bellow the cambium. I tend to remove the cambium and leave for a minute or so as any residual cambium will turn brown in the air. Scrape this off and then make sure the top cut is tidied up with a very sharp knife.

OK, now I'm confused.

I have been under the assumption that the purpose for removing the live tissue around the site of the air layering is to cut the flow of nutrients and water from using the normal pathway and for the area furthest from the roots to then work to get its water and nutrients through the moss "bridge", forcing it to grow roots to aid in the process.

I've always removed all live tissue well into the deadwood center to achieve this separation.

If you leave a pathway for water to move up the plant to the section to be air-layered, aren't you at risk of by-passing the air-layering cuts and foiling your attempts to force root growth?

Jay

Hi Jay,

Whilst I'm no pro and lack any hardcore experience, I believe the water conducting vessels transfer the fluid UP to the leaves, whilst the nutrients the leaves generate are sent DOWN to form stem or root growth. The way I understand it, removing up to and including the cambium, results in the nutrients having no where to go but potentially out, if surrounded by a moisture retaining material, thus forming roots.

Here's a "proper" article on the topic: http://www.evergreengardenworks.com/airlayer.htm

Brent

There's an excellent (really excellent) article with pictures by a member of the EdG forum, but it's in French. But the graphic part is very well done, and scientific terms are very often the same.

I't a digest of various messages on the forum :

La marcotte de A à Z

Ahem, as I said - all the way to the wood and then a BIT more. Exactly as it is shown in the excellent diagrams on your linked (French) discussion, thanks Alain. By a bit, I mean continue to scrape until fibres of heartwood are being lifted. In this way you can be certain that you have interrupted the cambium layer all the way around. If you don't do that, it will bridge the gap and heal over.

Kev Bailey wrote:Ahem, as I said - all the way to the wood and then a BIT more. Exactly as it is shown in the excellent diagrams on your linked (French) discussion, thanks Alain. By a bit, I mean continue to scrape until fibres of heartwood are being lifted. In this way you can be certain that you have interrupted the cambium layer all the way around. If you don't do that, it will bridge the gap and heal over.

Kev, the heartwood is dead and conducts nothing. The softer wood beneath the cambium is where the sap stream is. If airlayering is done at the right time, the cambium separates from the sapwood very easily, too easily.

That depends on the species, Will. On some it is very soft and scrapes easily and others can be a bind to make certain it is all removed, especially if they are contorted Yews! Ones I've layered succesfully using the method I described: Hornbeam, Nothofagus antarctica, Wisteria, Chinese Elm, Zelkova, Oak, Trident Maple, 3 types of Mountain Maples, Olive, Punica, Prunus mahaleb, avium and cerasifera and probably a few more. Only failures, so far, were multiple air layers from a Mountain Maple, possibly because it may already have been infected and later succumbed to verticillium wilt.

thank you every one especially alain for the diagrams, the tree i am layering is possibly a wild crab, haven't seen any roots yet... if the air layer doesn't work (knock on wood) can i just scrape off the callous and dig a little deeper in to the tree?

I knew I'd forgotten some. Add Malus to that list. The least succesful in terms of good rootage though. Five years after separation, it has developed into an unstable small tree with a decidedly one sided root system. I've got some other crabs to try next spring. Brent Walston manages to do them from cuttings, so it should be possible. Some crab apples are easier than others it appears.

Most broadleaves usually do root in one season or occasionally fail completely, in my experience. If it is still alive you can try removing any callus apply rooting hormone and rewrap.

Kev,
What recommendations do you have for layering Malus? I have an airlayer going right now on a large Crabapple branch I believe it is Sargentii. What kind of time frame did it take for yours to root? and also until removing from the mother tree? It has been about 3 weeks since I began the layer (which is late in the season for my area I know) and I have not yet inspected it for root growth. I was thinking of removing it in the first week of September hopefully to allow it to prepare itself for the winter. It would make a very nice tree if it takes and does well, but it is also part of my experimentation. Anyone else with knowledge on this species please chime in. Currently most of the trees I have are more experiments than proper bonsai, although I love the creation of bonsai, a large part of my enjoyment is the propogation and collection of trees. Thanks for any help, advice, and/or tips.

Todd

Mine took a couple of months to form a very few roots on one side. It is an unknown variety (but looks like "John Downie") planted as a pollinator for the orchard and regularly pruned. I should've insulated the layer with bubble wrap and left it on the tree over winter but I chose too early removal. It survived but was definitely not a text book airlayer. Every one of my other species formed a good nebari. Many to the point where I have to remove some roots to prevent them having too many, all radiating perfectly from the same point.