Because air layering is in the strict sense of the word a method of propagation it is generally treated under that heading, but since it deals more with the appearance of a particular plant than the increasing of stock, we are going to deal with it here. Air layering, or Chinese air layering, as it is sometimes called, is a method by which a long-stemmed, leggy plant can be cut back to size. At a point several inches below the lowest branches make a vertical incision in the stem about two inches long and about a third of the stem diameter in depth.
Using a plastic paper as a cover (the polyetheline bags in which potting soil is sold are good for this purpose) bind sphagnum moss around the cut and water thoroughly. Keep the cut covered and watered and in about eight weeks new roots will have formed at the cut. At this time the top of the plant can be cut off just below the new roots and the plant rooted in a new pot filled with your regular potting soil. The old plant can be discarded.
The seasons at which pinching and pruning are best vary from plant to plant and so we can’t give you any hard and fast rule when to perform these operations. However, most gardeners feel that spring or fall are generally the best times of the year.