Most house plants are propagated by either leaf, stem or leaf-bud cuttings. However, large-leaved plants with a hard, woody stem may become too large and difficult to propagate by these methods. These plants may include Dieffenbachia, Dracena, Ficus (Rubber Plant) and some Philodendrons. Such plants may be propagated by the process of air layering. This method allows a portion of a plant to root while still attached to the parent plant. Your new plant should be only 8-10 inches tall; a bigger section of the original plant requires more roots than will develop in air layering.
Make a cut halfway into the stem at the point you wish new roots to appear. Depending on the health and structure of the plant, you may want to stake or splint the section of the plant above the cut. A match, toothpick or small coin should be inserted into the cut to prop it open. Apply moist, not wet, sphagnum moss around the area of the cut and fasten it in place with a piece of polyethylene film (plastic sandwich bags work well). Then the polyethylene film should be bound top and bottom around the stem forming an air-tight ball.
The plant may take several weeks to root, particularly in fall or winter when less light is available, so check the sphagnum moss periodically to be sure it is moist. When roots appear, sever the rooted cutting from the parent plant and plant it in potting soil. If you do not want to dispose of the parent plant, you can try cutting it back to within an inch or two above the soil surface. Some species will develop new shoots fairly quickly.
The steps in air layering.