Although stem cuttings are the most common way to propagate shrubs, layering is another easy way to grow more plants. Layering involves rooting the stem tip while it is still attached to the parent plant, which provides water and nutrients to the new plant. This results in a larger plant in a shorter amount of time than rooting stem cuttings. Layering works best with plants that have drooping or limber branches that can be bent to the ground without cracking or breaking. It should be done in spring or summer to allow the new plant to form roots, although some layers (new plants) may take as long as two years to root.
Choose a supple limb from 1/4 to 3/4 inches in diameter for the layer. Use a dormant one-year-old shoot in the spring, or a limb from the current season's growth that has hardened in the summer.
Bend the limb to the ground, and mark where it lays on the ground. Use a trowel to dig a trench 3 to 4 inches deep and 6 inches long for the limb.
Use a knife to make an angled cut 6 to 8 inches from the end of the stem tip. Coat the cut with rooting hormone.
Lay the limb in the trench and use a peg or landscape pin to hold it in the trench. Cover the stem in the trench with soil, leaving the stem tip bent up. Hold the stem tip in an upright position and firmly press the soil in a 4 to 6 inch high mound around it
Insert a small wooden stake in the ground next to the stem tip. Use lightweight string to tie the stem tip to the stake so that it remains upright.
Place a 2 to 3 inch layer of straw, shredded leaves or sawdust mulch in a 12-inch diameter circle around the stem tip. Water thoroughly.
Leave the layer attached to the parent plant until the following spring. Do not let it dry out. In the spring, pull on the layer gently and check for roots. If it has several roots, use a knife or hand pruners to cut the limb of the parent plant away from the layer as close as possible to soil.
Plant the new plant in a container or in the ground. Remove one-third of its leaves if the leaves are small, or one-third of the leaf area if the leaves are large, to help the new plant adjust. Keep the plant shaded and well watered for one to two months to give it time to get established.