Layering is a plant propagation technique where a stem or branch develops roots while still attached to the parent plant. This method encourages root growth by manipulating the stem, often covering it with soil or other material to promote root formation. Once rooted, the new plant can be separated from the parent.
Types and Methods of Layering
Several methods exist, depending on the plant and desired outcome:
- Simple Layering: A low-growing stem is bent to the ground, pegged down, and covered with soil, leaving the tip exposed.
- Tip Layering: The tip of a stem is bent to the ground and covered, allowing roots to form at the buried tip.
- Compound Layering: Multiple points along a long stem are buried to encourage root development at each point.
- Air Layering: A section of a stem is girdled (partially cut), treated with rooting hormone, and wrapped with moist sphagnum moss, often covered with plastic to retain moisture, to induce root formation before separating the layered section from the mother plant.
Several references define layering in similar terms, emphasizing the attachment of the developing plant to the parent during the root development process. For example, the Oklahoma State University Extension states that layering is "a technique of plant propagation where the new plant remains at least partially attached to the mother plant while forming new roots." The North Carolina State Extension similarly defines it as "the development of roots on a stem while the stem is still attached to the parent plant."
It's important to note that "layering" has other meanings in different contexts, such as in geology (referring to rock strata) or in software (describing the arrangement of data or images in distinct levels). This answer focuses on the horticultural definition.
