I've tried air layering a couple times and my impression has been that it's far more difficult than grafting onto rootstock.
First, with rootstock you just plant it when you get it. With air layering you can mess it up by planting it too earlier...or too late. As with grafting, in air layering you can also mess up the process by making improper cuts, but a messed up cut in air layering can ruin the whole branch (think completely detaching the branch). With grafting, if you mess up the cut in the scion you can usually just re-cut the scion wood a little higher up. Finally, you can mess up air layering my having too little (or too much) moisture in the moss around the forming roots. With grafting, you just wrap the graft as best you can.
I have to agree with John. Attention to detail in this type of work is what makes the difference between success and failure. What I've found is that with grafting, you spend maybe 10 minutes making everything just right, then you get it wrapped up and just walk away and let the seedling do the rest. Air layering requires constant attention over a multiweek period. Forget or get delayed and it's all dead. Give grafting a try. It's not black magic. A putsh like me got 80% success in my very first try.
Air layering is not hard, or mystical. The prep work is also easy, what is or makes it seem difficult is knowing which trees/ shrubs will accept this method of propagation easily and grow well. To air layer you need 1. a good subject plant. 2. sharp knife that is sterile 3. large amount of sphagnum moss soaking in a container of water till you are ready to wrap it on the stem. 4. enough plastic sheeting to go around the stem/sphagnum ball (or one of the rooting cups shown in the above post by Cee Ray) 5. two lengths of string to tie the ends of the plastic wrapped moss ball 6. rooting hormone powder.
To make a stem ready to grow roots (air layer) 1. select a longish stem, remove leaves 4 leaf pairs back from growing tip. 2. in this section of the stem you just stripped the leaves from, use the knife tip to remove some rectangles of bark down to the cambium layers, go around the stem making at least three of these "rooting zone" spaces 3. dust the newly cut rectangles with the rooting hormone 4. Wrap the new root zone with the sphagnum moss (don't wring it out, you want it wet) so the moss ball is at least 3" thick all the way around the stem. 5. Wrap with the plastic sheeting so that the ball is covered with two wraps of the plastic and it should extend at least 3" above and below the moss ball for tying space. 6. tie first string at the bottom of the moss ball making it snug but not strangling the stem. repeat at top of moss ball. Now stand back and smile, walk away. If you are in a hot climate, check the ball every week to make sure it is moist, if it is just right moss might be greening inside the wrapper, don't worry. Hard to root trees may take as long as 6 months before you see roots growing through the moss ball. Once you see well formed roots coming through the moss ball all the way around, simply use your pruning shears to snip off the branch below the bottom of the moss ball, if you are planting this directly in to the ground, prep your hole before you remove the strings and unwrap the moss ball, which is now your new root ball. Trim off the stem under the new roots but do leave at least one inch so you don't damage the new roots. Plant like you would any other tree/shrub.
I have air layered at least 2000 trees in my life. I have had fewer than 20 failures.
Grafting is also not really hard once you get the techniques down, both have their places in the propagation of trees and shrubs. It mostly depends on if you have a root stock tree or if you want a non grafted trunk. some trees actually don't take well to grafts just as some trees don't take well to being air-layered.
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posted 4 years ago
That's a great overview Bryant, thank you.
Have you ever air-layered an apple rootstock? Just curious because I have a bunch of M9 rootstocks in the ground that we budded in August, and they each have 2 or 3 good size branches. Ideally I would like to air layer them all starting in the spring.