Blossoms or fruit are removed from branches before air layering.
Air layering is an asexual or vegetative method of propagating trees without planting seeds or taking cuttings. Roots actually form while the potential cutting is still on the tree. By remaining attached to the tree during root formation, the air-layered branch receives sunlight and a natural environment. Another advantage of air layering over rooting cuttings is less frequent monitoring. Make air layers on last season's wood during spring or on new wood in late summer.
1
Place a handful of sphagnum peat moss for each intended air layer in a sealable plastic bag, pour water into the bag and seal. Sphagnum peat moss used for air layers must be thoroughly moistened, which can take an hour or more.
2
Select a branch approximately the diameter of a pencil and locate a node -- a leaf bud -- approximately 12 inches from the tip of the branch.
3
Cut a ring around the circumference of the branch -- a girdling cut -- approximately 1/4 inch below the selected node, cutting through the cambium -- bark -- but avoid cutting into the wood.
4
Make a second girdling cut in the same manner 1 inch below the first cut.
5
Slit the band of bark between the two girdling cuts with a vertical cut and loosen the band.
6
Remove the band of bark and scrape any remaining cambium off of the exposed wood.
7
Dip a cotton swab into the rooting hormone and apply the hormone to the exposed wood on the branch so that the rooting hormone clings to the surface of the exposed band.
8
Open the sealed bag of sphagnum peat moss and take out a handful of moss.
9
Hold the moss in place around the exposed band on the branch while covering the moss with polyethylene plastic wrap.
10
Secure the plastic wrap with twine or electrical tape.
11
Check the air layer every few weeks to maintain adequate moisture in the peat moss and to monitor rooting progress.
12
Sever the branch below the rooted band after roots fill the peat moss. Tree-branch air layers generally take one season to form roots.
Things You Will Need
Sphagnum peat moss
Sealable plastic bag
Sharp knife
Hormone rooting powder
Cotton swab
Polyethylene film (plastic wrap)
Twine or electrical tape
Tip
Sterilizing equipment used for plant propagation is a common practice. However, Ventura County Cooperative Extension of the University of California refutes the value of equipment sterilization, indicating there is potential damage to equipment through caustic chemicals such as alcohol or household bleach and that benefits for disease reduction are not proven. Be on the safe side and wash your knife with soap and water and rinse well. Dry with a clean paper towel.
Warning
Propagating grafted trees by air layering is not recommended. Trees grafted onto root stock take on certain characteristics of the roots, such as disease resistance or increased hardiness. A rooted branch from a grafted tree does not express all the characteristics of the parent tree.
http://homeguides.sfgate.com/root-tree-branch-cutting-35815.html