How to Air Layer A Japanese Maple

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This article will explain how you can propagate a Japanese maple by air layering.
by Maple Tree · All Zones · Techniques & Methods · 0 Comments · September 11, 2014 · 19,063 views

Air layering is a method of creating a new tree by removing a large branch or section of the trunk of another tree. Before the branch is removed it is girdled, protected with peat moss or other growing media and the girdled section is allowed to root. After rooting the branch is removed from the tree.

As a Japanese maple collector I am always developing new trees for my gardens, containers, and bonsai projects. Many would call me a Japanese maple addict as I just can't stop wanting to produce more of these beautiful trees prized for their beautiful coloring, different leaf characteristics, attractive colored trunks and branches, and their interesting growth habits. Although the Japanese maple can be propagated by seeds and cuttings my success rate using air layering has been much better. Growing from seeds of course takes much longer to produce a tree large enough to plant out in the garden or create a bonsai tree with a nice size nabari. There is always the chance also that when growing a plant from seed you may not get the same desirable characteristics as the parent plant. Propagation from cuttings or air layering will create new plants that are identical to the parent. The air layering method of propagation is one that forces roots to develop on a branch while it is still attached to the parent plant.

The principal of air layering is to injure the wood of the parent tree so that the flow of nutrients from the parent tree's roots still support the layering's leaves but the flow back from the layering's leaves to the parent trees' roots is interrupted. The injured part of the parents tree bark slowly heals at the same time forming adventitious buds that will form new roots into the growing medium that has been placed around the injured area of the limb. Although the parent tree is used to support the layered limb and leaves the food energy produced from the layering's leaves is used to build new roots of its own and not allowed to move down to the parent trees roots for storage and use by the parent tree. When the layering has produced sufficient roots of its own, it can be separated from the parent as it can now support itself.

The best time for layering is in the spring just after the first leaves have developed and the parent tree is putting on new roots of its own. There are many methods others use in air layering to hold the growing medium around the layering. Some use plastic containers (soda bottles) cut down their length, placed around a limb, then filled with a light, well-draining potting soil or sphagnum moss. I like to apply wet potting mix or sphagnum moss around the layering area, wrapped and held in place by plastic sheeting. No matter what method you use or develop yourself they will all work well as long as your growing medium is held in place and can be kept moist. I like using plain old clear plastic kitchen wrap (Saran Wrap). It is easily used to wrap around the limb and growing medium and tends to stick to itself making a nice snug wrapping. Being clear it is easily seen through when checking soil moisture and root growth. The plastic wrap can easily be opened at the top around the limb when adding water to keep the growing medium moist.

Below are the steps in air layering a Japanese maple. This method also works well on many other trees and shrubs you may want to propagate by air layering.

  • First you want to choose a suitable limb that will produce a tree that meets your needs. You may want to produce a tree with a straight trunk or maybe a trunk with some character that may be crooked or has a limb coming off it at an interesting angle. Take your time in deciding where you want the trees roots to start and where and how you want your trees canopy to look. How your trees canopy will look may depend on the limb structure you choose above your air layering. I normally like to choose a limb that is at least an inch or thicker. If choosing smaller limbs they may need to be supported so that they won’t break with the added weight of the growing medium in any wind or being hit by something. When possible try and choose a limb that is easily reached as you will have to keep the growing medium moist and check the progress of root development periodically.

  • With a sharp knife cut two matching slits completely around the branch approximately 2 inches apart from each other. If possible make the upper most slit just under a leaf node. This is where a leaf would appear along the stem. Cut another slit lengthwise between the two slits that were cut around the limb. Normally you can lift the outer bark and tissue under the bark at this slit and peal them off easily between the two slits that were made around the limb. You want to make sure all the bark and underlying soft tissue is removed between the two slits. The underlying tissue is normally green in color and can be scraped off down to the hard wood underneath if it doesn't peel off easily. Don't worry about scraping too deep into the hard wood when removing the outer bark and underlying tissue. Cutting into the hard center wood won't hurt the development of new roots. You just don't want to remove too much hard wood. Removing too much of the hard or center wood may weaken the branch allowing it to break more easily before roots have developed and the limb is separated from the mother tree.

  • Brush or sprinkle rooting hormone on the area that you removed the bark and underlying tissue from. Rooting hormone can easily be found at most any nursery or garden center.

Go to page 2 for the next step in air layering.


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