Many a gardener has noticed that branches of some plants seem to take root and form new plants where they lay on the ground. This is a natural process known as layering. We can take advantage of layering to increase the number of plants in our collection or to share our prized plants with friends and family.
The concept is similar to propagating by cuttings except, in the case of layering, new plants remain connected to the mother plant until after roots form. The mother plant provides water and nutrients while the new plants take hold. After roots are established, the new plant or plants can be severed from the mother plant.
Types of plants best adapted to the layering method of propagation are those with sprawling stems that lay along the ground or those with flexible stems that can be bent to the ground and pinned down to keep them in contact with the soil. Many plants have sprawling branches that grow horizontally along the ground, including mint, thyme and most ground cover-type plants. Where stems contact moist soil, rooting will occur, and each section of stem that has its own new root system can be cut from the mother plant, resulting in several plants. This method of propagation is known as “simple layering.” Some plants, such as forsythia, spirea and roses, may not send their branches along the ground naturally, but the stems can be bent gently to the ground and pinned with wire or other support to hold the stem in contact with the soil.
Raspberries often grow long canes that bend over until the tip of the cane touches the ground. After a few weeks, roots will form where the stem contacted moist soil. Once the roots have established, the new plant can be severed from the mother cane, resulting in two separate plants. This method of propagation is called tip-layering.
Some plants have upright stems that tend to become bare at the bottom as the plant grows. Many houseplants, including rubber tree, schefflera and fig, fit this category. You can rescue those plants with a technique known as air-layering. Many gardeners are squeamish about this method of propagation, since it requires cutting a substantial wound into the stem, but the wound stimulates the plant to form roots.
Choose an area on the stem just above a node (The area where a leaf was attached to the stem.) where you would like the new root system to grow. Remove the leaves in that area and make an upward slanting flap with a 1- to 1.5-inch cut almost to the center of the stem. Brace the cut open with the end of a match stick or toothpick to keep the wound from resealing. Another method of wounding that works well with woody stems is to remove the bark completely around the stem in a 1- to 1.5-inch long section where you want the new roots to grow.
Apply a rooting hormone to stimulate faster rooting, then cover the wounded area with a generous handful or two of moistened sphagnum moss. Both the moss and the rooting hormone should be available at local garden centers. To keep the area moist, surround the moss with a sheet of plastic and close it around the top and bottom with a twist-tie.
Roots will become visible in the moss after several weeks. At that time, the top of the plant can be severed just below the new root system. Repot the new root system in a suitable container, and you’ll have a new plant that is vigorous and well-endowed with foliage!
Last updated: 11 April 2006