other methods of layering aside from air layering
Layering The horticultural layering process typically involves wounding the target region to expose the inner stem and optionally applying rooting compounds. In ground layering or simple layering, the stem is bent down and the target region buried in the soil. This is done in plant nurseries in imitation of natural layering by many plants such as brambles which bow over and touch the tip on the ground, at which point it grows roots and, when separated, can continue as a separate plant. In either case, the rooting process may take from several weeks to a year.