Airlayering / Groundlayering
Airlayering is a very suitable method for getting material for bonsai for free. It is very easy, and almost full proof way of propagation. Some trees are fast and take less than 3 month to develop roots, depending on the season, and some might take more than 2 years. But most trees are fast, and even for big branches, up to 20cm+, you can have material in no time.
Why do airlayers fail some time:
-You did not make the ring barking wide enough and the callus of the top section joins with the lower part of the trunk. ( be careful with figs)
-You did not remove all the callus, and the callus simply regenerated without the need to form roots.
-You did it during the wrong season.
-You did not tie the packet around the medium tight, so that water is not lost.
-Even when doing an air layer in a packet you will need to water…perhaps every two weeks, which is much less than in an open pot. Some airlayers I had forgotten to water during the whole period, and they still survived, because the packet was water tight.
-In case of pot open on top being used, you did not keep it moist at all times.
-You used the wrong medium
When is the best time to do airlayers:
In tropical countries, I do it all the time, except winter and second half of autumn.. Roots are able to grow as long as the temperature is above 10*C. At lower temperatures the root formation is slower. So spring and summer can be a good time to airlayer your material.
Which is the best place to do it?
Look at as many branches in easy to access position.
Be brave and go for fatter branches 10-15+cm. It will save you time growing a trunk, later.
Remember that the top edge of your ring, will be where all the roots will come from, and that is where your nebari will be, and will be eventually exposed on the surface of the pot. So imagine the part of the branch you are Airlayering sitting on top of the bonsai pot.
So when trying to select a place to airlayer, I try to use the same criteria as selecting a nursery material for trunk qualities. Thickness, taper, movement and suitable branches. Avoid places with reverse taper by all means.
Look for a place where a large branch joins, and you have some thickening of the trunk. Put your top edge of the ring at the widest part, or some distance bellow in order to use it as the first section of your trunk, and use the side branch as e second section of the trunk. Remember the first section of your trunk should be 1/3 of the final height. look for a place with a branch you can use as a leader, or even some suitable branches. For short the one that looks that will need less work to become a finished bonsai.
Avoid making more than one airlayer on the same branch.
How to do it:
After you selected the place, mark a ring around the tree, and cut deep
along the mark, making sure, you cut through the bark and the cambium. That first cut might be horizontal or somewhat slanting. Imagine how the tree will slant ones you position that surface horizontally in the pot.
Make a second cut parallel to the first one and away from the first cut, at list as the diameter of the trunk or more, in the same manner as the first cut.
If you are airlayering a tree that is a prebonsai, and you would like to keep the bottom part, remember to leave enough space for the roots to grow, and be able to cut the pot/ plastic together with the roots, without disturbing them. Depending on the diameter of the airlayer, I leave in pots for smaller airlayers 5-6cm bellow the first cut and 2-3 cm more when in packet, bellow the first cut for the lower part of the pot or packet.
Remove all the bark and the cambium, making sure no cambium is left. If you remove somewhat deeper, it will do no harm to the tree.
tie a thick wire bellow the first cut, very tightly, to prevent the cambium re growing. (optional)
Add some rooting hormone along the top edge of the ring bark . (optional) Or use a onion to rub there. Willow twigs mashed/pounded…can also do the job. I don’t use anything and very rarely have an airlayer that does not root.
Next get a clear plastic packet, large enough to wind 2 times around the media, wrap it around the trunk twice, while gathering it evenly, 6-15cm below the top cut, and tie it very well with a string. Fill inside with sphagnum moss, or coarse sand, and water it. Twist the packet, tight around the media, making sure the media is all around the branch, and tie it on top very well.
Cover with a black packet on top in the same manner. I like to keep the packet inside transparent in order to be able to inspect the roots, without disturbing them. Some people use kitchen foil instead of the clear plastic. I use two plastics, since it assures me better of being airtight.
This packet I did not tie on top, but used it like a pot, since there are two branches airlayered at the same time.
Tied it with wire to prevent the packet from collapsing.
a pot can also be used for airlayering
See how leaves were reduced/ removed.
Another way to airlayer, so that larger area is created for more root development. Picture courtesy of Noryadi Norrudin
Another way to do it is using a plastic pot, for places that are easily accessible and easy to water. Cut the side of the pot reaching the centre of the bottom and make a hole there, large enough to accommodate the branch. Use in this way the pot instead of the plastic. You can insert 3 nails under the bottom of the pot, or tie it to some branches above, so it does not slide down. Tie it around first so the cut does not open, when you add the media. Add the media and water it often, to keep it moist.
I would suggest not to check it at list for 2 month. Ones you see it has enough roots , trim the top part to reduce the leaf mass, and cut it off, without disturbing the roots.
Plant in coarse river sand or bonsai media, after removing the plastic and securing the plant to the pot so it does not move. I don’t normally disturb the roots at this stage. They are very easy to break. I do it much later when the plant is established. Best time to remove an airlayer is spring so it has enough time to grow.
If you used a pot, just cut it under the pot, and let it recover. Reduce some of the foliage .
Recovery process should be at list 1 month under light shade. Do not fertilize until you see good growth, 1+ month later.
Ground layering is the same as airlayering but is done at ground level, to remove roots that can not be coorrected or shorten a tree that has a nice top.
Not sure who the owner of the picture is.
I cut off a ring from a pot and fill it with bonsai mix,