Layering

Air Layering

Air layering is used to shorten established plants, as well as to produce relatively mature new specimens, and is akin to growing from cuttings, except that root formation is accomplished prior to removal of part of the plant. Rooting thus becomes easier, though air layering may itself not work. It is certainly more energy-intensive, and should be used only if other methods are more difficult or less reliable, or where more mature specimens are desired.

Early summer is the ideal time, except where otherwise marked. Cut upward into the bare stem at a 45 degree angle, about 1 1/2-2" deep, and place a matchstick in the upper end of the cut to keep it open. Dust the cut surface with rooting powder. Soak sphagnum moss in willow extract or vitamin B1 solution overnight, and work into and around the cut, to form a ball extending several inches either direction, held in place by clear plastic. Keep moist, and support the weakened stem if needed.

Alternatively, a 1/4" ring of bark may be removed from around all or most of the stem. This is a heavy injury for any plant, but may be necessary to root more difficult specimens; it also results in faster rooting. Leaving a small 'bridge' in place can still allow for some movement of water and nutrients, and lessens the amount of injury sustained. Cover the wounded area in moss, as before.

Less drastic than ring-barking, and much slower, tourniquet-style air layering involves looping copper wire around the trunk of a selected stem, just below a nodal junction. The wire is pulled tight until it begins to cut in-to the bark, then, the area is again wrapped in sphagnum moss.

When roots are seen, possibly many months later, cleanly cut the new plant off, not disturbing the root ball, and pot up. A light peat-rich medium will be easiest on the new plant. Trim remaining stump. Keep both warm and shaded for several weeks.

Simple Layering

This technique basically consists of burying the mid-section of a branch, and allowing roots to form on the buried part, prior to severing the new plant from the parent. Select a young, healthy, low-growing shoot, ideally one pruned the previous season, and from early spring to mid summer, dig a shallow trench in well-worked, well-draining soil, to layer it into.

Remove side shoots and leaves from the branch, except from its very tip. Next, cut a small strip of bark, 2" long, from the branch some 10-12" from its tip, and brush with rooting hormone. Bend the branch into the trench and peg into place, bending the tip of the branch so that it points up out of the soil. Stake the tip in an upright position.

Keep the branch well watered until rooted, and sever from parent in mid-fall. Check late fall or the following spring: if good root development has taken place, the layer is ready for transplantation.

Tip or Trench Layering

A variant on simple layering, this technique involves burying the actual stem tips, and awaiting the growth of a new plant. In late summer, bend stem tips toward the ground, and bury them vertically some 3-4" into good, well-draining soil. New plantlets will develop, and are removed and re-planted the next spring, including the distal tip of the original plant. Place the new plantlets in 6" holes and fill half way, gradually filling it completely over the growing season, or simply replant even with soil surface.

Serpentine Layering

 

An easy and natural variant again on simple layering, this is most suited to plants with long, flexible stems, and involves burying some 4-6" of stem 3-4" deep, bringing it back above soil surface, and a few inches further burying it again, etc., until the full length of the stem has been used up in this manner. Each section can be separated off and replanted, the following season.