Air layering an acacia

Has anyone out there ever managed to airlayer an Acacia karoo? I have one with a very bad root structure and a too tall trunk.

Hi Marco

Have a look here. Been a discussion on the SA bonsai forum lately.
http://www.sabonsai.co.za/forum/index.php/topic/1840-air-layering-acacias/page__hl__%2Bacacia+%2B

Some say yes some say no...

Brett

I approach these questions by considering the risks and options:

One can always air layer without risk if the alternative would be to chop the top off. The girdle interrupts the phloem and cambium through which auxin flows toward the roots, just as chopping off the top will. This is most effective in stimulating new sprouting below when done after the foliage has hardened.

On the other hand, the OP's objective apparently is to keep the top and to create new nebari which is risky and irreverisible. However, layering near the ground level is more favorable than near branch tips. The tree can be lost if there is no foliage (or no new foliage appears) below the girdle. Photosynthates that feed the roots are transported via the phloem which is interrupted at the girdle; so the roots will be starved by the girdle if there is no foliage below the girdle to feed them.

Still it is possible that new roots will not emerge from the top of the girdle after two or even three seasons, which brings me to the final option. One could buy some small seedlings and install them as approach grafts at the level where the new nebari is desired. After they are established, the top would be supported by the seedlings' roots and could be 'harvested'. While this is a possible way to salvage a failed air-layer it does raise the question of why not use approach/thread grafting to repair/refashion the existing nebari? Thread grafting can also be used to put new branches where you want them.

IMHO, the bottom line is just make the air-layer if the tree is not precious at this point.

If it is precious,

• get another and use it as a test
  
• air-layer a branch you don't want - if it succeeds, so too will a low trunk layer
  

• If you have ready availablility of 0-2 year seedlings, maybe go with approach/thread grafting instead. Other than a few scars, it doesn't put your prescious tree at risk.
  
  
  
  
  
  
  
  
  
  
  

Thanks Brett, I did ask there once and was wondering if the ibc would have more info. This new thread, though, has way more info.

0soyoung, the grafting sounds like it could be a solution. I'm going to try that and also air layer a branch.

Hey, i thought i remembered a video i watched where someone air layered and brazilian rain tree which i believe is a common name for an acacia https://www.youtube.com/watch?v=8Bp7-iZ2zec not about the species in particular but proof that it is done.

thanks, yes, it is the same family so that's promising.

Same family but very different. Even different Senegalias (Acacia) will behave differently.

Soetdoring, Senegalia karoo, is well know for its very week root structure. That's why normally they only live to about 16 years of age, and then they fall over. A huge one just fell over in the Stellenbosch botanical gardens. They can of course get older, that one was, but it was cared for. In nature karoo will never get that big.

Airlayering would proof very difficult, and I dare you to take it on, and floor us all...

Senegalias normally like very deep pots, then the rootsystem takes off. How deep is your pot?

Love and light

Hi Andre

Thanks for additional info. It's in a medium deep pot at the moment, but it's had such a bad time this last year (neighbour didn't water it while I was away and it nearly died), I'm thinking of putting it into the ground. I'm going to to try and airlayer a branch. I've got nothing to lose at the moment.

I'm curious to know if the air layer worked. Any feedback?

Brett Simon wrote:Hi Marco

Have a look here. Been a discussion on the SA bonsai forum lately.
http://www.sabonsai.co.za/forum/index.php/topic/1840-air-layering-acacias/page__hl__%2Bacacia+%2B

Some say yes some say no...

Brett

Not found on server.

Geo that forum closed down some time ago...