Whip Grafting/Tounge Grafting Practices
What is whip grafting? Whip grafting is defined as a plant graft prepared by interlocking a small tongue & notch in the obliquely cut base of the scion with related cuts in the stock. The whip graft is helpful for plants that unite easily. It can be used to graft root, stem graft or top graft. It is the predominant propagation method used on apples & is widely used on pear. While most grapes are grown from cuttings in this country, whip grafting is the standard when they are propagated.
Whip grafting is also called splice grafting or tongue grafting. The diameter of the scion & rootstock should be the same, from the size of a pencil to 10-15 mm.
Whip or tongue grafting has been the primary method employed in propagating pecan nursery stock in the southeastern United States. This technique is also used to some extent in the Southeast & west to Louisiana for top-working larger pecan trees on the aboveground portions. Since successful whip grafting is closely correlated to the presence of high humidity, this method has not been used widely in the drier sections of Oklahoma, New Mexico & Texas. A major strong point for a whip grafting nursery stock is the smooth & straight trees that are produced by this method. Some examples of the Whip grafting used fruit trees are apple, pecan, roses, mangoes, and pears.
Things required for Whip Grafting:
The Tools used for Whip grafting is;
- Grafting knife or similar sharp knife
- Scion wood
- Grafting tape – It is used for reinforcing the union between the rootstock and the scion & protect the graft from the air and water, which cause dehydration.
- Grafting wax – Grafting wax is a composition of rosin, beeswax, and similar materials, used in gluing & sealing the wounds of newly grafted trees to protect them from infection.
- Tree label
- Waterproof marker pen.
Whip Grafting steps:
The steps for Whip grafting are;
- Seedling rootstocks, one to two years of age, are usually used for whip grafting purposes. The diameter of the upper portion of the root normally ranges from 3/8 to 3/4 inch; however, stocks up to one inch in diameter can be used. The season for the whip or tongue grafting is February to early or mid-March in most areas, or while the stock is dormant.
- Select one year graft or scion wood in the dormant season. Size must correspond to the size of available rootstocks. Each graft stick must contain at least two sets of buds. Graft wood should be selected & stored in late January. A knife with a thin blade shaped as made from high-quality steel is desirable for whip grafting. Make sure that the knife will take a fine edge & hold it under a heavy workload.
- Expose about four to six inches of the upper portion of the taproot. Where only a few trees are involved, the entire method of soil removal may be accomplished by the use of a hoe. However, if the graft is protected with poly tape, the graft can be placed above the soil line as well. Grafter is poised to create an initial slanting cut on rootstock. Note down the slight angle of the knife blade. The stock of the seedling rootstock fits into the groove or notch formed by the thumb & forefinger of the knife-hand. This serves to stabilize the stock & to provide a guide as the cut is made.
- Pull the knife upward with the blade angled about 45 degrees, making a smooth & the straight diagonal cut. This slanting straight-plane cut must be 2 to 3 inches long. Try to create this cut with one stroke of the knife.
- Place the knife at a spot on the slant cut approximately one-third of the distance from the tip to the bottom of the cut. Create a “tongue” cut by working the knife blade downward for a distance of 1 to 1 1/2 inches. Take care to stop splitting the stock. Utilize fore-finger of the left hand to brace the stock. Note in the inset that the cut is neither parallel to the grain of the stock nor to the slanting cut, but is really between the two.
- Hold the scion wood securely in the left hand, but with concern to prevent injury to the buds. Place knife at an angle to the scion & make a slanting cut by pushing the blade away from the body. This straight-plane cut must be made as similar to the cut on the rootstock as possible.
- Create the “tongue” cut on the scion by placing the knife blade at a point about one-third of the distance down from the tip. Pull the blade downward at an angle that is about halfway between the grain of the scion & plane of the slant cut. Note that the thumb of the knife hand serves as a guide for a controlled cut, while the forefinger of the left-hand steadies the scion.
- Slip the plane slice surface of the scion down to the slant cut of the stock until the two “tongue” cuts mesh together. The cambium layers of the stock & scion must be aligned if a union is to be obtained. An uneven cut will result in gaps between the two surfaces. If the two cuts are made properly, the stock & scion will appear to be one.
- Wrap the graft steadily with masking tape or special grafting tape. Polyethylene budding tape may be used in this wrap but may require cutting at a later date to stop girdling. Make certain that the cambium layers of the scion and stock remain aligned during the wrapping procedure. Note down in the inset that the wrap extends from below the graft union to a point slightly above.
- Firm moist topsoil around the whip or tongue graft to prevent drying. Ideally, the soil must cover all of the taped areas with the lower bud group on the scion exposed. The cut surface at the top of the scion stick may be coated with wax to prevent excessive drying. If the graft was placed above the soil line, this step would not be necessary. Remember, regardless of the graft is placed above or below the soil, the tape which initially secured the graft must be removed. This can be done as late as one year, but preferably after three to four months.
Read: Bark Grafting Procedure.
Types of Whip Grafting:
The types of Whip grafting are mainly divided into three types:
Simple Whip Grafting:
This type of grafting practice includes the procedure of a simple sloping cut on both the scion and the rootstock. The two parts must overlap each other perfectly. In any case, one rule must be followed: The wider the scion & rootstock, the longer the cut surface.
Tongue Whip Grafting:
This method is more common in practice, especially in the case of pear & apple trees. It is used to graft very thin stems. It can be used on roots, stems or tops. The scion should have 2 or 3 buds with the graft made below the bottom bud. The first cut is a 2 to 5 cm sloping cut at the bottom of the scion. The second cut is completed with a distance 1/3cm from the tip of the first cut. The same procedure is repeated on the rootstock.
Root Tongue Grafting:
Root tongue grafting is used for propagation on a rootstock seedling; however, the rootstock cannot fit into the dwarf category. This is suitable for the fact that it causes the rooting of the scion. We use a piece of 8 to 10 cm long roots and a little bit longer scion. Root grafting is done when the apple rootstock & scion are dormant. This method is generally not used for pears.
In Whip grafting rootstock condition is dormant; active with bench grafting of container rootstock, greenwood grafting, and vegetable crops. While in cleft grafting rootstock condition is dormant; before active growth starts in spring.
How to make a Whip Grafting?
In Whip grafting procedure, the scion and the stock are cut slanting & then joined. The grafted point is then bound with tape and covered with soft wax to prevent dehydration & infection by germs. This is considered the most difficult to master but has the highest rate of success as it offers the most cambium contact between the scion & the stock. It is the main common graft used in top-dressing commercial fruit trees. It is normally used with stock less than 1.25 cm diameter, with the ideal diameter closer to 1 cm & the scion must be of roughly the same diameter as the stock.
The stock is cut during on one side only at a shallow angle with a sharp knife. The scion is similarly sliced through at an equal angle starting just below a bud so that the bud is at the top of the cut & on the other side than the cut face.
A notch is cut downwards into the sliced face of the stock & a similar cut upwards into the face of the scion cut. This act, as the tongues & it requires some skill to make the cuts so that the scion and the stock marry up neatly. The joint is then taped around & treated with a tree-selling compound or grafting wax.
The elongated “Z” shape adds strength, removing the requirement for a companion rod in the first season. The joint is then taped around & treated with a tree-selling compound or grafting wax. A whip graft without a tongue is less stable & may need added support.
Care used in Whip Grafting:
The Whip grafting care will be as follows;
The graft needs to heal before the new tree will start to grow. This can take anywhere from a couple of weeks to a couple of months, based on the conditions. Once the top bud has grown an inch or so you can be happy your graft has taken & you can move the plant into a sunnier location.
Once it is clear that the graft has successfully taken cut off all but the strongest shoot, generally the top one, as well as any growth below the graft. Eliminate any other shoots for the first few years of growth.
Carefully eliminate the tape around midsummer. If it has taken the graft must be healed and the young tree growing. If you wait too long to remove the tape, you can strangle & kill the graft.
Grafts that have taken & grown over the summer can be planted over the winter, or grown on for another year first. If you plant them out the winter after grafting, make sure to clear the area of plants as these will compete for water & may grow to out-shade your young tree or make a microhabitat that is humid. If you grow them on for another year before planting out, pot up after the first year to refresh the soil & give the roots space to develop outward rather than forming a tight ball or winding around the container base.
Read: Techniques In Vermiculture.
Advantages of Whip Grafting:
The whip and tongue are stronger because the interlocking tongues are held under compression by the natural elasticity of the wood of both stock & Scion. This naturally generates the pressure needed for graft union formation, which is discussed in the section on Requirements for Successful Grafting & Budding. The additional length of the vascular cambium exposed along the cut surfaces of a whip and tongue graft is much greater than the length of cambium exposed by only the slanting cut without the tongue, in the case of a splice graft. This results in greater cambial contact between stock and scion of a whip and tongue than of a splice graft.
Ease of propagation: Because the scion is not easy to propagate vegetatively by other means, such as by cuttings. In this case, cuttings of an easily rooted plant are used to give a rootstock. In some cases, the scion may be simply propagated, but grafting may still be used because it is commercially the most cost-effective method of raising a particular type of plant.
Read: How To Grow Avocado Fruits.