Richard Bogren, Gill, Daniel J.
For Release On Or After 05/25/12
By Dan Gill
Propagating plants means to create new plants from those you already have, and you can do that in many different ways. Planting seeds and rooting cuttings are two of the most common methods of propagation. But another technique, called layering, is useful in propagating a wide variety of ornamental plants. Now is an excellent time to layer plants.
The major difference from stem cuttings is that layering stimulates roots to form on the stem before rather than after it is removed from the parent plant. Layering has some real advantages over taking cuttings. Layering is often successful with plants that are difficult to root from cuttings. Also, a much larger piece of the plant may be rooted when using layering, so you get a bigger plant more quickly.
As with other forms of vegetative propagation – such as cuttings, division, grafting and tissue culture – using layering to propagate a plant creates offspring that are genetically identical to the parent plant. This means that you can create as many as you want of exact copies (clones) of a plant with desirable characteristics.
Despite all the recent hoopla over cloning animals, people have been cloning plants for thousands of years. Many or most of the ornamental plants in your landscape and home are clones, and most of the fruits and nuts you buy in the supermarket are produced by clones.
Layering can be done with herbaceous or woody plant materials. It is most often used on woody plants because they tend to be more difficult to root from cuttings. But layering can also be very useful for herbaceous plants, especially when you want to root a relatively large piece. I have layered coleus, ruellia, ornamental sweet potatoes and impatiens to name a few.
Simple layering, as the name implies, is the easiest method to use. Its main requirement is that the plant must have a branch that is low enough and supple enough to bend to the ground. If such a branch is not available, a variation called air layering can be used – but more on that later.
Here are the basic steps for simple layering. You will need a sharp knife, rooting hormone, a brick or stone, and a trowel.
1. Select a low, supple branch that can be bent to the ground without breaking. A part of the branch at least 8 to 12 inches back from the tip should be able to touch the ground.
2. Bend the branch down and determine what part of the branch will come in contact with the soil and where it will touch the ground.
3. Use the trowel to dig a shallow hole (about 3 inches deep) in the soil where the branch touches the ground.
4. Use the knife to wound the branch at the point where it touches the ground. The branch must be wounded to induce roots to form, but do not completely cut through it. You can use one of several techniques:
–Scrape off a ring of bark about 3/4 inches wide.
–Cut a notch about half way into the branch.
–Make a slanting cut into the branch (toward the branch tip) about halfway through it and wedge it open with a small pebble or twig.
Then dust the wound or cut with rooting hormone powder. This step generally is not necessary to induce root formation on herbaceous plants.
5. Gently bend branch so that the wounded area is in the shallow hole, then cover it with soil. Place the stone or brick on top to hold the branch in place because it will tend to spring back. At least 8 to 12 inches of the end of the branch should be sticking out of the soil.
Roots should readily form at the wound during the warm summer months. Herbaceous plants root in as little as four to six weeks, but you should give woody plants, which root more slowly, four to six months. It won’t hurt to carefully dig around the layer occasionally to check on root formation. When you see well-developed roots (at least 1 to 3 inches long, depending on the size of the layer), cut the branch at the point just behind the roots. Then you can pot the new plant or plant it into the landscape.
Air layering is done on plants when no branches can be bent to the ground, but the principles are the same. Wound a branch using one of the above techniques, dust it with rooting hormone and wrap the wounded area with damp sphagnum moss. While holding the moss in place, wrap it with plastic and secure it in place by tying or taping it above and below the ball of moss. Do not allow the moss to dry out during rooting. Check periodically for roots, and cut off the layer just below the roots when they form.
Layering is one of the easiest and most reliable methods of propagating plants. It makes a wonderful gardening project, and you can use the resulting new plants yourself or give them to gardening friends.