The method involved in growing bonsai from ground or soil layering is also similar to that of taking cuttings as far as it is founded on the principle of generating natural growth of roots from a shoot. However, there are some differences too. In the ground layering technique, root growth is encouraged even without severing the cutting from the parent plant. In this case, roots begin to grow after a portion of the parent plant's branch is buried into the soil or any other growing medium that promotes rooting. In fact, this is considered to be a relatively gentle propagation method, as the cutting is not separated from the parent plant till it has developed proper and robust roots.
The best time of the year to undertake ground layering is mid-spring. First, select a branch having a good form and ensure that it is sufficiently low to reach to ground. Subsequently, mark a point on the branch approximately one foot from the branch end and dig a hole into the ground having a depth of about 4 inches. Blend equal parts of peat moss, preferably made from ground bark, and sand with the soil dug out from the hole.
For growing bonsai via the ground layering technique, cut the selected branch in a slanting manner on its underside. Subsequently, place a small stone inside this cut. Next, twist the branch back inside the hole ensuring that you do not break the branch. It is important to attach the turned branch into a vertical position. Finally, cover the place where you have put the branch in the hole with a specially prepared soil and water it properly.
The branch (also known as layer) will develop roots in about 9 months to a year's time. When you find that the branch has rooted properly, you can severe it from the parent plant and pot it in a bonsai container or tray. While you are severing the layer from the parent plant and transferring it to a pot, ensure that you sever the stem immediately beneath the original cut.
When you layer softwood plants, they will generally develop roots much earlier - in about 6 weeks to 8 weeks. After the layers have rooted, ensure to sever them from their parent plants and pot them in bonsai trays or pots. Remove all new buds using your fingers until the time the layered stem has developed a good and mature root system. It is important to keep in mind that the layered area should always be kept moist with a view to ensure the quick development of the root system.
The ground layering technique to develop new plants is most effective for those plants whose branches can be easily brought to the ground or soil. This way you can increase the number of your bonsai quickly and without any difficulty. This technique involves selecting a robustly growing shoot, generally selecting a shoot that is about a year old offers the best results. Second, a one inch long slit is cut from the parent plant in a manner that it tips at a position where the shoot will be touching the ground. Subsequently, the shoot is attached to the ground in a manner that the incision is allowed to remain open, while the shoot remains firm. To end with, cover the split part as well as the peg with about two inches to three inches of sandy soil that is compressed and watered appropriately. Sometimes, it may be necessary to hold the layer in place with the help of a stake and ensure that the shoot is firm. When you do this, you will be able to avoid any damage to the young roots while they develop.
Several plant species, such as azaleas, lilacs, maples, chaenomeles, cryptomeria, jasminum nudiflorum, pomegranate, rhododendrons and others, reproduce readily via the ground layering technique. On the other hand, a number of old Prunus amygdalus (commonly known as almond) and P. Persica (commonly called peach) plants send up suckers from their roots. These suckers can be collected from the roots and developed as new plants. Currently, chosen varieties of both prunus mentioned above are generally available on plum stocks. As a result, bonsai growers do not have any much interest in the plum suckers. Nevertheless, many growers have claimed to have successfully grown new plants by sowing the stones collected from the fresh fruits. In addition, it is really worth digging up suckers from any of the above mentioned plants to develop them as new bonsai trees.
Ground layering technique is a method whereby roots develop where a shoot or branch of a tree comes in direct contact with the soil. In fact, this is considered to be a spontaneous type of propagation. It occurs naturally in the case of plants having trailing branches like wild rhododendrons.
This method involves fixing a low growing branch of a tree into the ground. It is necessary to anchor the branch to the ground using a small wire that is bent in the shape of "U" with a view to prevent the branch from moving and then covering the place with soil to promote root growth. Moreover, it would be excellent if you take a portion of the parent tree's bark off and add it to the soil to encourage rooting. Usually, the layered branch is left undisturbed till the next spring, by which time it should have developed roots. When you find that the layered branch has rooted at the place where it is in contact with the earth, sever it from the parent tree, dig it up and transfer it into a bonsai pot. In case you have selected a conifer tree for ground layering, it would be best to remove the soil from where you have cut the branch to examine whether or not enough roots have developed. If the branch has not formed sufficient roots, you should leave it undisturbed for another year. Ground layering with a wild fig will result in formation of adequate roots in a very short span - possibly just within a month's time.
This propagation technique is nearly akin to the natural happening and possibly this is the reason why it is called simple ground layering. This method involves bending a branch low enough to touch the ground below and then fixing it firmly in that position with a wire loop. Subsequently, the portion of the branch that is in contact with the ground is covered with soil lightly, while the remaining part of the branch is supported with the help of a stake. You need to brush the buried portion of the branch with hormone rooting powder as well as score the bark lightly with a view to promote root formation.
Generally, simple ground layering is undertaken when the plant is in its dormant period, as this will help the roots to appear in spring. You can severe the layer from the parent plant in autumn, but only after being sure that it has developed enough roots. In case, the layer has not rooted well, you should allow it to remain attached to the parent plant till the next winter.
If you want a layer to root in a pot, all that you need to do is bend the branch into a pot so that a portion of it is in contact with soil. The remaining part of the technique is same as in the case of rooting a layer in the ground. You will find that it would not be easy to make some branches sit in a pot in the manner you desire. In such instances, you need to provide special care to prevent the place of potential layering from moving out of the pot. Therefore, it is advised that apart from wiring the branch to keep it firm in the spot, you also use stakes to ensure that it does not move or "spring" from the container.
The propagation technique is only successful when it is undertaken with shrubs that have the aptitude to endure heavy pruning. Stooling involves severe cutting, pruning of the bush down to its crown prior to the beginning of the new growth season. Subsequently, the base of the plant should be covered with soil. When the shoots start emerging in spring, you should know that enough new roots have developed from the plant's base, just higher than its crown, underneath the soil. You can clear the mound or soil covering and expose the layers, which can be planted outside during the subsequent winter. At this stage, you can see the formation of new roots and in case they are not sufficient for the individual plant to survive healthily, you should desist from cutting the layers from the parent plant. Instead, allow them to remain attached to their parent plant for another year.
This propagation technique involves stripping a branch of all its leaves, while leaving the leaf buds (also known as "eyes") undisturbed. Subsequently, the branch is laid on the ground and covered with soil. In due course, the leaf buds or eyes will give rise to vertical shoots that emerge from the soil to develop into rooted layers. In order to separate the vertical shoots, you need to simply severe the parent branch between the newly developed shoots. The Chinese layering technique should be undertaken during the winter months after the shoots have sprouted.
The method of propagating bonsai trees is a variant of the simple ground layering method discussed above. In the simple ground layering method a branch is buried along the ground once. In this case, the branch is bent and staked a number of times with a view to form a series of undulations. Apart from this difference, the simple ground layering and serpentine layering methods are just the same, with the bottom portions of the branches being fixed to the ground where it is in contact with the soil. Both methods involve scoring and dipping the branch in contact with the soil in hormone rooting powder. The process involved in severing the cuttings from the parent branch is also same as in simple layering.
Before concluding the discussion on the subject of propagating new bonsai trees via ground layering, it is worth mentioning here that among the various methods discussed above, it is advised that the simple ground layering technique is the best means to produce a new bonsai plant. This is primarily because the simple ground layering method allows the bonsai grower to select the style they desire. In this case, the grower is able to select any specific branch for its shape. However, while undertaking the ground layering technique to develop new bonsai trees, you ought to ensure that the part of the layer above the ground is properly supported with stakes. If this is not done, the layering may become distorted while new roots are developing.
Undertaking simple layering in a pot has its own advantages, as it helps the new plant avoid the shock of being transplanted. Moreover, you should always keep in mind that the cuttings should be watered properly both before as well after they are severed from their parent plant.