I just bought a 4foot maple from lowed on clearance. I paid 30 dollars for this tree. The leaves were burnt but new buds were coming on. The base is about the size of a 16oz soda bottle. I would like to learn everything on airlayering before the spring comes.
Can the great members post the best way for a novious to airlayer.
Don't worry I know to wait to spring. Ill post photos tomorrow
You must have a dwarf variety to have that thick a trunk on a 4 foot tall JM - or are you talking about the nebari ring at the base and not the trunk caliper?
At any rate, where I live it takes at least 90 days to get to a harvestable air-layer. My daily high temperatures are only in the 70Fs and so root growth is slower than it might be in places where the average daily temperature is in the 70F to 80F range where maximal the root growth rate occurs.
Regardless, if you are going to air-layer a vertical stem (trunk or branch) you can cut a plastic pot, wrap it around the trunk, and fill it with bonsai soil, instead of the usual plastic bag full of sphagnum. One typically gets big fat fleshy roots with the traditional method and then has to develop 'hardened' roots in a pot after cutting the layer off. With the pot-of-soil method this all happens at the same time. Furthermore, the whole works can be left on the tree until spring if need be - your new roots are no more at risk than the mother plant's potted roots.
I put screws in the trunk to support the pot. Of course, you must do something to keep the bonsai soil from falling out the drainage holes and the hole you made to accomodate the stem. There are lots of possibilities but a bit of damp sphagnum works well. Next, fill with your favorite dampened bonsai soil. I try to leave it alone for three days before watering to allow the rooting hormone to be adsorbed into the tissue. Then, just water the rooting pot every time you water the mother plant. If you use an non-compacting inorganic soil like Turface, you can occasionally shake the soil away from the top of the girdle to see how your roots are doing. I have also started layers with the traditional bagged sphagnum method and switched to the pot after the hormone has had time to do its thing. I tend to do this on 'hard to root' trees.
In principle the soil-in-a-pot method could be done on any stem. But, I find placing a pot on a horizonal branch troublesome as also with any stem on an angle that requires making a second hole in the pot (i.e., the open top of the pot must be up). Maybe you will have a clever way to deal with it.
The girdle (where you cut off a ring of bark) ought to be one or two times the width of the stem. Usually this means the two cuts around the stem are going to be an inch or two apart. Callus will eventually form on both ends of the girdle which will narrow the gap. If you make the girdle too narrow, the girdle can 'bridge' and you'll not get roots.
Having done this, scrape the green stuff (cambium) off the wood. If you don't get it all, the residual cambium can regrow and 'bridge' the girdle. But you can add some insurance by wiping the girdle with a 'sani-wipe' or with your favorite grain alcolhol (that suff they make in TN is great and makes air-layering a lot more fun - one for the tree, one for me ...) - this will kill any residual cambium. Then dust with your favorite rooting hormone (1.6% IBA works for most deciduous trees) and close it up in your choice of moist environment.
Lastly, there is a well-known 'cone of juvenility' - the shoots nearest the ground are the easiest to root. So air-layering trunks near the ground tend to be easiest and air-layers in the crown of the tree tend to be more difficult (longer time to make roots and fewer roots are produced). The rooting competence of the tree overall declines with age. In other words, producing adventitious roots on a 80 year-old tree is more difficult than an 8 year-old one. The best location for air-layering in both, though, is on the trunk or shoots near the ground.
