Layering is a technique for propogating plants. It works best for plants that grow roots slowly, and plants that would naturally grow roots where a stem touches the ground. To layer a plant, you usually take a stem and bend it down towards the ground, or into a pot, and hold it in place. You damage the stem where it touches the ground by cutting it part way through, adding some rooting hormone if you want. After some time, the plant will grow roots and shoots at the cut and it can be removed from the parent plant. Layering can also be done in the air by cutting a stem part way through, adding the rooting hormone, and bundling up some damp potting soil or peat moss around the cut. The plant will grow roots into the bundle of soil, and then it can be removed from the parent plant. This works best with plants that aren't flexible enough to be bent to the ground.