Seed is the most familiar method of propagation. However, some popular plants produce no viable seed. Some produce seed that is genetically very different from its parents. For many plant varieties, only vegetative propagation reliably produces similar copies. Such copies can grow from division, cuttings or layering. They are genetically identical clones.

Layering is uncommon for nurseries because it is generally insufficiently productive. It is unpopular for home gardening because it seems complicated. It is actually more reliable for many species than cuttings are. Also, layering is quite practical if merely a few copies are sufficient for home gardening. Realistically, it is not as complicated as it seems to be.

Layering is simply the development of roots where stems lay on the soil. All sorts of flora does it naturally without intervention. For example, ivy vines notoriously develop roots as they extend over the ground. Tips of raspberry canes develop roots where they leap over to reach the ground. These rooted tips grow replacement canes that repeat this process.

With a bit of intervention, several species that do not commonly layer can do so also. For some, it can be as simple as pressing a lower stem into moist soil. Application of rooting hormone to exposed cambium accelerates layering for most. Gouging into the underside of the buried portion of stem exposes its cambium. Tip growth must remain above grade.

For most species, the buried portions of layering stems should be a few inches in length. Extra stem length is no problem. Actually, if stems are long enough, they can be situated into their permanent locations. Stems can layer right below grade, but they prefer to be a few inches deeper. While their roots develop, they require irrigation for evenly moist soil.

The few inches of foliated tip growth above grade sustains actively layering stems. Also, remaining intact cambium provides sustenance from the original plant. Only a few stems can layer simultaneously, but that is enough for most gardens. Hydrangeas, azaleas and camellias layer quite easily. Pines, oaks and eucalyptus do not. Layers should develop quite a few roots before separation.