In air layering (or marcotting), the target region is wounded, or a strip of bark is removed and then encased in a moisture-retaining medium such as sphagnum moss, which is further surrounded in a moisture barrier such as plastic film. Rooting hormone is often applied to encourage the wounded region to grow roots. When sufficient roots have grown from the wound, the stem is removed from the parent plant and planted. It can take the layer from a few weeks to one or more growing seasons to produce sufficient roots; this is largely dependent on the plant species and the vigor of the parent plant.