Grafting can be described as a horticultural technique used to bind together dissimilar plant parts to enable them to combine into a single unit that will not only continue to live, but also thrive. In the case of fruit-bearing trees, they will also produce delicious fruits. This technique entails grafting a part of one plant, may be a branch that is about a year or two years old, which is called the scion onto a different plant generally belonging to the same species and called the stock. While the stock develops a new root system as well as the lower trunk, the scion develops the upper trunk and the crown of the new bonsai tree. While the fused parts from different trees grow into a new tree, they also remain their respective individuality or characteristics. This is obvious from the different types of shoots on top and under the grafting point. In addition, the thickness of the trunk above and below the grafting point also varies and in many cases you can see dissimilar patterns on the barks of the stock and the scion.
In fact, grafting has various uses for any bonsai enthusiast. He can employ this technique to develop an entirely new tree according to his wish, subsequently keep improving the tree and also maintain it. In addition, the grafting technique can also be employed to prevent the damaged roots of bonsai trees from dying. At the same time, this technique is useful to enable flowering trees to produce flowers of a variety of hues and forms.
There are several plants that are difficult or almost impossible to propagate using various methods. However, the grafting technique can not only make this possible, but the bonsai grower can develop them as per his/ her desire. In fact, it has been proved that white pines have grown more rapidly when they were developed by grafting using other roots than other means. This is the main reason why people in Japan graft all white pines on the stocks of black pines.
Grafting also offers other advantages. It enables us to produce various plant strains. However, it is another issue that as far as their look and color are concerned, the plants will always be consistent with the scion. On the other hand, even sowing seeds from the same plant may often produce a large number of different varieties.
On the other hand, grafting also has its downsides. It has often been seen that the when the grafting has been undertaken does not heal properly and, this not only looks unattractive, but may even give rise to growth of ugly shoots just lower than the spot. Moreover, grafting technology is not easy; it not only involves some skill, but also considerable experience.
As far as the bonsai growers are concerned, the most important types of grafting include lateral grafting, crown or rind grafting, wedge grafting, branch grafting and bud grafting. All these types of grafting are discussed briefly below. Generally speaking, it is best to undertake all grafting at the start of spring, before the plants commence their growing season. However, in the case of evergreen trees, the grafting technique can also be undertaken in the latter part of summer.
This form of grafting is generally undertaken during summer and is mainly applicable to conifers and evergreen trees with broad leaves. It is carried out to propagate new plants of the above mentioned varieties. While making the graft, you should ensure that it is as low on the lower trunk as possible with a view to prevent it from showing up afterwards. Preferably, the graft should be concealed by applying some earth. Next incise the scion into a wedge measuring roughly anything between 3 cm and 5 cm in length making a slanting cut of about a similar length on the tree trunk of the stock. Next, insert the scion in the slanting incision on the tree trunk. Use raffia to fasten the scion and the stock together before sealing the grafting point using grafting wax. In fact, grafting wax is used in all types of grafting to prevent infections to the wound and also help it to recover faster and better. Sealing the graft point will ensure that the wound does not dry out and also put off water and different pests from entering the trunk through the wound.
In the following year, you will notice new growth from the scion - an indication that the graft has been successful. When this occurs, you should cut and remove the stock at an angle higher than the grafting point. On the other hand, if you do not desire to propagate a new plant employing this method, but you simply like to put in a branch on a trunk that may appear to be excessively long, you should ensure that one side is kept shorter on the scion while you are sharpening one end of it to make a wedge. While inserting the scion into the stock the shorter side should be closer to the trunk. This should be done in such a way that the scion protrudes from the trunk with a curve that appears normal.
Bonsai experts generally try wedge grafting only on somewhat slender branches as well as trunks. In case the thickness of the trunk exceeds 3 cm, they usually prefer to undertake the crown or rind grafting method. When you undertake the crown or rind grafting method, it allows you to form several trunks or enable you to create the somewhat older trees afresh with a secure root system. You can also repair an inferior or injured crown by removing the crown of a particular tree from its stock and adding new branches.
When you are undertaking crown grafting, the scion has a relatively smaller diameter compared to the stock. To begin with, you need to saw through the stock neatly and then smooth it off using a sharp knife - this will help the cut to recover faster and better. Subsequently, make a perpendicular cut measuring anything between 2 cm and 5 cm in length along the side. Tap the two folds of the bark gently till they become loose and subsequently place in scion that has been prepared from before. You can simultaneously arrange a number of scions in the region of the trunk by employing the same method. When this step is complete, apply grafting wax on the grafting point as well as on the stock's cut surface.
On the other hand, the wedge grafting method involves making an opening measuring roughly 3 cm deep and similar to the direction of the trunk's growth. Next, you may either insert one scion at the side or two scions one at either side. The scions should preferably be 5 cm to 7 cm in length and already sharpened to form a wedge.
Once you have firmly secured the scions with raffia, you should seal the place of grafting using grafting wax. Wedge grafting is one method that you can use to insert new branches into a tree trunk.
In the case of bud grafting, rather than using a scion, you only use a little portion of a bark along with a properly formed heel that is cut off from the scion and placed in the stock. In effect, the heel is the dormant bud that lies at the conjunction of the leaf axil and the trunk. Bud grafting is an excellent means for inserting new branches.
Summer is the ideal time of the year for undertaking bud grafting. During this time of the year the bark is complete with heel and will separate from the trunk without much difficulty. In fact, you should ensure that you always collect the bud from the present year's growth on the tree. Opt for a rather cool and rainy day since this will be helpful in preventing the bud from drying up very quickly. Use a very sharp grafting knife to create a T-shaped cut in the scion. First make the vertical cut, which should be roughly 2 cm in length across the xylem, but ensure that you do not make the cut very deep. After the vertical cut, you may undertake the horizontal cut to make it look like the alphabet T. After making the T-shaped cut, take away the bud from the scion, only leaving behind a small portion of the bark measuring just about 1 cm across in the region of the heel. In case the heel is accompanied by a leaf, get rid of it and just keep the leaf-stalk attached to the heel.
Next, peel back the bark on the T-shaped cut carefully using a sharp grafting knife. Open up the flaps of the bark and slide the heel inside from above. Provided it is required, use the leaf stalk as a lever to slide the heel inside. Subsequently, tie up the graft using raffia or a rubber band. However, you need to leave the heel free. The graft will be taken when the leaf stalk falls off on its own and a new branch grows after spring.
Before you decide to undertake bud grafting to develop new bonsai trees, you ought to know that this process is most appropriate for developing new fruit trees, for instance, apricot, peach and cherry. You may also use bud grafting for roses. This technique is particularly recommended for bonsai growers if they wish to transform a deciduous tree into monoecious tree, such as in the case of sea buckthorn as well as prunus-leaved holly. It is important to remember that these plants will produce fruits only when both the male as well as female trees are present in the same place. When you insert a bud taken from a male tree and insert it into the stock of a non-fruit bearing female tree, the bonsai grower will be able to develop a new tree that will self fertilize and also bear fruits.
The branch grafting method does not involve directly cutting off the scion. On the other hand, the scion is allowed to remain attached to the parent plant for the time it takes to combine with the stock. In fact, branch grafting is ideal for all bonsai species and it is frequently undertaken on plants, which serves both as the stock as well as the scion.
Branch grafting involves cutting away a narrow piece of the bark, measuring about 3 cm long from the scion as well as the stock, ensuring that the cut sections on both are consistent with one another. Next, place these two - the scion and stock, together and secure them firmly using a rubber band or raffia. Finally, seal the grafting point with grafting wax.
It is unlikely that the graft will take before it is late autumn in the same year, provided you undertook the grafting some time in spring. You should separate the scion from its parent plant only after the graft has taken in late autumn. While separating the scion from the parent plant, ensure that the cut is made very close to the stock with a view to keep the bump small. If you apply the grafting wax, the wound will not only heal quickly, but also better. You can also prepare any particular tree for branch grafting. This can be done by allowing a branch to grow very near the place where you want to undertake the grafting and bind it down afterward for grafting.
When you are growing evergreens and conifers as bonsai, it is important that you remove the scions from the parent plant right away prior to grafting. On the other hand, you need to wait till growth has stopped during autumn and winter, prior to cutting the scions of deciduous trees. It is advisable that you do the grafting on a frost-free day. After you have removed the scions, stick them in moist sand and keep them in a cool place beyond the reach of frost.
In normal situations, the stock and the scion are taken from the same plant species with a view to make sure that the graft will be successful. In fact, bonsai growers undertake all the methods mentioned above just using a sharp-edged knife. They do not require any other tool for carrying out these processes.
While undertaking grafts, it is vital to complete the entire process very quickly and with maximum sanitation with a view to prevent any bacterial infection on the newly created wound on the trees. In fact, this is the reason why the bonsai growers should never touch the wounds with their hands or fingers.
Once the grafting is over, place your bonsai tree in an area where there is no wind and the temperatures are stable. Ideally, the plant should be kept under a wrap of plastic film or in a hotbed propagator. When you find that the graft is successful, you should slowly, but steadily acclimatize the bonsai tree to the usual conditions prevailing in the environment. After a year, you should remove the raffia.
