Of all the plant propagation methods you might use in your garden, the most natural ones make use of layering techniques, so named because you create a new “layer” of plants from the old one. The most common procedures, called stem layering or tip layering, involve bending over low stems and helping them to root into nearby soil. The mother plant is left undisturbed, and the new plant is not severed until a sound root system has established. With time and patience you will get a bigger, huskier plant than you would get by rooting cuttings, and if you keep it up, you will always have vigorous young plants coming along.
The goal with all layering techniques is to convince a stem to change its ways and start developing roots, which herbs such as sage, lavender and thyme are willing to do with a little encouragement. If you want only a few new plants, the simple stem layering technique is easily mastered. First you select a stem that wants to bend over, and slightly wound it at the point where you want roots to grow. A scrape with a fingernail or knife will do, as shown below with rosemary. Then you cover the wounded section with enough soil to keep the stem moist, topped with a stone to hold it in place, and wait.
You can wait a couple of months or a whole season to dig and move the new rooted plant. If you look closely at the top photo of garden sage, you will see that the mother mound is accompanied by a smaller plant to the right. This is a fully rooted new plant grown using the layering technique. It has since been dug and moved to a fresh spot.
Mound Layering Lavender
Other herbs including rosemary, thyme and oregano are easy to propagate using the simple layering technique, but the low-maintenance method I most like to play with in spring is called mound layering. Let’s say we have an old lavender plant which has gone woody. If given the chance, she still has the stuff to make a strong comeback. Instead of digging up the old plant, we can change her destiny and turn her into a lavender plant nursery using the mound layering technique: As soon as spring leaf buds begin to show, cut back the plant to 3 inches (8 cm) tall, and mulch with 6 inches (15cm) of light-textured soil. Add a top mulch in summer. The many lavender stems that emerge from the mound can be allowed to bloom before being cut back by half their length.
In late summer or the following spring, you can disassemble the mound with your fingers, separate and sever the stems that show the heftiest root systems, and transplant them into containers or a new location in the garden. Lavender is a slow example of the mound layering technique, but some plants are much faster. Hardy chrysanthemums that are cut back and mounded over in spring will produce a crop of nicely rooted offspring by early summer, as will a potted rosemary plant that is severely cut back and sunk to its rim in the garden.
Layering Fruits and Nuts
Hazelnuts, walnuts and several fruits including apples, blueberries and gooseberries can be propagated using the mound layering method, which I discovered by accident two years ago after rescuing and transplanting a neglected little blueberry plant. Feeling sorry for the stalwart thing, which had survived repeated assaults with mowers and weed whackers, I spoiled it with water and a deep sawdust mulch. I have since been rewarded with at least 20 new stems, each with a good start of roots down in the mulch. Not what I wanted, but blueberry plants have proven popular among friends and neighbors, so the story has a happy ending.