If you grow decorative foliage plants such as aralias, dacenas, dieffenbachia, and of course rubber plants, the time will come when these will lose their looks by stretching tall and dropping lower leaves. At this point you still admire the tops but you find the plant as a whole for from attractive. However, by a method known as layering (actually another means of propagation by stem cutting) you can save the handsome tops and get rid of the bare stems. With a sharp knife, cut halfway through the stem at the distance from the top that you decide will make an attractive plant.
From this crosscut, split the stem upward for about 2 inches, and dust the inside of the cut with a rooting hormone. At the top of the cut, insert a small sterile object, such as a piece of wood or a pebble, to keep the split open, and press a small pad of moist sphagnum moss into the slit. Wrap more moist moss over the wound and around the stem, covering an area of about 2 inches above and below the cut. Cover the moist moss with a plastic wrap to retain moisture, and seal top and bottom of plastic wrap with tape or tie with plastic plant ties.
The root system that develops from the cut will penetrate the moss and be visible through the plastic covering. When roots appear adequate to sustain the top growth, remove plastic and moss. Just below the rootball, cut through the stem of the parent plant and pot up the new plant. If you cut back the lower part of the old plant to about 2 inches it may send out new shoots and you will have two plants. With dieffenbachias, you can cut the old stem into 2-inch sections, lay them on a bed of sand or peatmoss, cover lightly with either, and keep moist until shoots emerge from the ends of the cuttings and the bottom sides of the sections have developed roots.
The many new plants can then be separately potted and probably widely distributed to friends.