If gardening is a love affair with the plants in your yard, then plant propagation is the gardener's equivalent of having children.
Saving seeds is the most well-known way to perpetuate and expand a plant collection, but plant layering deserves more attention. One of the easiest propagation techniques, layering produces new plants by encouraging roots to form on stems that are still part of a parent plant. After the roots have formed, the section of the branch bearing them is removed from the original plant and planted out on its own. This way, a parent plant supplies all nutrients until the new plant gains an adequate root system and can survive on its own.
With long flexible branches, deciduous shrubs like forsythia, red and yellow twig dogwood, mock orange, viburnum varieties, rose of Sharon, and spiraea respond well to this technique. In addition, evergreen shrubs with low branches that reach soil level, like azaleas and rhododendrons, are often layered. Many vines lend themselves to a modified form of layering, and multiple plants can be produced from a single stem of clematis. Usually performed in the spring or in the fall, it's usual to wait a full year before severing the new plant. Each season has its advantages and disadvantages, but late summer and fall layering can provide the most number of suitable shoots to be rooted. Here are three techniques to help you get started.
Simple layering involves bending and covering branches with soil and holding them in place until rooted. The branches are often scraped, cut, or otherwise slightly wounded on the under side at the point where the stem is covered. This will encourage the quick formation of roots, especially with the aid of a rooting hormone. Any part of the branch covered by soil should have all leaves cleanly removed. Often, roots will form at this juncture of leaf and stem.
Tip layering is performed by digging a hole 3 to 4 inches deep. Insert the tip of a branch and cover it. The tip will grow downward at first, then it will bend sharply and grow upward. Roots will form at the bend. The new tip that emerges from the ground becomes the new plant. This method works well for propagating purple and black raspberries, and trailing blackberries.
Compound (serpentine) layering is similar to simple layering also, but many layers can result from a single stem. Bend the stem into the soil as for simple layering, but alternately cover and expose sections of the stem. Each section should have at least one leaf axil or bud exposed and one covered with soil. Wound the lower side of each stem section to be covered. This method works well for plants producing long, vine-like growth, such as wisteria, clematis, and grapes.
Mound (stool) layering is useful with heavy-stemmed, closely branched shrubs. Cut the plant back to 1 inch above the soil surface in winter. Buds will produce new shoots in the spring. Mound soil over the new shoots as they grow, just as you would treat potatoes. Roots will develop at the bases of the young shoots. Remove these shoots in the next dormant season. Mound-layering works well on apple rootstocks, spiraea, quince, daphne and magnolia.
While not an overnight answer to increasing the number of plants in your yard, layering is an easy, reliable reproduction method. They also make meaningful gifts "¦ especially for your children.