WW-00532 Reviewed 2009
The whip graft is used mostly on young apple and pear trees when the branches are relatively small (not more than ½-inch in diameter) and the understock is about the same diameter as the scion of the new cultivar.
CutCut off a branch of the understock, leaving a stub at least a foot long. Make a straight, slanting cut about 1½ inches long on both the scion and the stock (see A and C in Figure 1). Make the cut straight and evenone stroke with a sharp knife will do it. For the tongue, make a straight draw cut (not split), beginning near the top and cutting about the full length of the level (B and D).
Figure 1. The whip graft is usually used for grafting root stocks and scions but can also be used for grafting small branches.
UnionMatch the two parts together (E). Unless the scion and stock are the same size, be sure the scion is in contact with the inner bark on one side. If the toe of either the stock or scion extend beyond the heel of the other, cut if off evenly.
Tying and coveringBind tightly with tape, then carefully cover the union and binding material with grafting compound.
This type of graft is difficult for the beginner but is used extensively by experienced operators. It lends itself to the tape method of binding. Tape serves to seal the wound and bind the parts together.
While other types of grafts depend on the bark slipping well, the whip graft does not. In fact, it is best if you make this graft before the narrow tongue of wood.
AftercareRemove wrapping as soon as the scion has started to grow to prevent girdling of the tree.
The cleft graft is used for topworking older established apple and pear trees, either on the trunk of a small tree or on the side branches of a larger tree. It is best adapted to branches 1 to 2 inches in diameter. The grafts are made within 2 to 3 feet of the trunk or main branches and preferably not more than 4 to 6 feet from ground, or new top of tree will be too high.
CutsSelect a place free from knots and cut off the stock with a saw. Cut the cleft (avoid splitting if possible) with a grafting chisel, large knife or hatchet. After a few trials you will learn the proper depth of cleft. In horizontal branches, the cleft should be sidewise, that is, not perpendicular, to reduce breakage from birds and storms.
With a sloping cut about ¼ inch above the upper bud, cut the scions to include three buds, and to a blunt wedge about 1½ inches in length with one side slightly thicker than the other (see A and B in Figure 2). If the scion wedge is cut to a sharp point there is danger of the bark peeling. Also a sharp scion wedge' will not fit the cleft as well (C).
Figure 2. The cleft graft is the one to use on large branches.
UnionOpen the cleft slightly with a grafting tool or screw driver. Insert a scion on each side, with the inner bark of stock and scion in contact. Have the thick side of the scion outward (B).
Keep in mind that the bark of the larger stock is thicker than the scion bark, so the scion should not be flush with the stock. A very slight tilt will assure a contact, at least where the cambium layers cross (D).
Tying and coveringThere is no need to tie, unless the stock is small and does not bind well. Cover the unions with grafting compound and be sure the cleft is covered its full length (E).
AftercareScions that are growing vigorously will need attention to prevent breakage by birds, ice and storms. Either tie the scion to a supporting brace (see B in Figure 3), or pinch back the tips before growth becomes excessive. For additional support, circle all the shoots from one stub with twine (A).
Figure 3. In this example of a cleft graft, three stages in the growth of a branch from a scion are shown.
During the first season, let all scions and the shoot growth from below the graft grow undisturbed. However, do not permit this understock growth to shade out the scions. The second spring, select the most suitable scion as the permanent branch and consider the others as spares. Leave the spare scions on to assist in healing over the stub, but cut them back to a few buds on each (see B). The third spring, severely cut back the spare scions again. In the fourth season, or when crowding is noted, cut off all of the spare scions as seems necessary (C).
Figure 4. Trouble ahead in the next storm. Don't let two leaders compete.
The Modified Cleft Graft
Instead of trying to master the whip graft or side graft, use a simple kind of cleft graft on small understock. Stock (see B) about the same size as the scion (A) may be split and a wedge-shaped scion inserted.
Should the stock be larger than the scion, be careful to set the scion to one side instead of on center (C). In this way the cambium of stock and scion will make contact.
Wrap this graft union (D) carefully with a good grade of rubber tape. As the graft grows the tape stretches and eventually deteriorates.
Very large trees are generally poor subjects for cleft grafting, so when grafting their large branches, a slightly different method is ordinarily used.
Carefully saw off the branch undercutting it first to avoid tearing the bark. You may need to recut the stub to get it smooth. Saw the branch to receive the scions, instead of splitting it.
Make two saw cuts about 4 inches deep at right angles to each other across the end of the stub, making a + shape. Then fit the scions into the four places made by these cuts.
Although the side graft is adapted to a wide range of branch sizes (¼ to ¾ inch diameter), its use is generally restricted to branches that are too large for the whip graft yet not large enough for the cleft graft. As the name suggests, the scion is inserted into the side of the stock, which is generally larger in diameter than the scion.
CutsSelect a smooth place on the understock branch at least a foot from the trunk. Make a slanting cut at a narrow angle almost to the pith (core of the branch) (see B in Figure 5). Cut the scion to a short, sharp wedge (about 1 inch) with one side thicker than the other (see A).
Figure 5. In the side graft, the cut goes across the grain to reduce splitting.
UnionBend the branch slightly to open the cut. Press the scion in so the cambium layers of the stock and scion meet at one side (C).
Tying and coveringTying is unnecessary if the stock binds well, but you may have to tie small materials if the scion is not held firmly. Cut surfaces should then be covered with grafting compound (E).
AftercareIn about two weeks, cut off the stock above the union (D) using sharp shears in order to avoid disturbing the scion. Then cover the cut surface with grafting compound (D).
If the graft has been tied, cut the binding shortly after growth starts; this will prevent girdling. In the first season, you may allow some shoot growth from below the graft, but do not permit this growth to shade the scion growth. After the first season, all growth should be cut off, except that of the graft.
Inspect grafts during the growing season to guard against faulty covering or binding. If shoots are attacked by fire blight, cut them 6 inches below the visible symptoms.
Budding is a form of grafting in which a single bud is used as the scion rather than a section of stem. It is the most commonly used method for fruit tree production in the nursery, but can also be used for topworking plum, cherry, apricots, and peach as well as young apple and pear trees. (Cherry, plum, apricot, and peach are not easily cleft grafted or whip grafted.)
Budding is done in the summer, usually from July 15 to August 15, when the bark of the stock slips easily and when there are well-grown buds. The first step is to cut bud sticks of the desired cultivar from strong shoots of the present season's growth (see A in Figure 6). These buds should be mature, as indicated by a slightly brownish color.
Figure 6. In budding, a single bud does the work of a scion.
Clip off the leaves as soon as the bud sticks are cut, leaving about ½ inch of the leafstalk for a handle. Discard the soft tips of the bud sticks. Wrap the bud sticks in moist burlap, moss or paper to prevent drying out.
Branches from the size of a lead pencil up to ½-inch diameter may be worked by this method. The bark of larger branches is too thick for satisfactory budding.
CutOn the branches of the stock, about 15 inches or more from the trunk, make a T cut just across the bark (C). Then, with a knife blade or bark separator, lift the corners and carefully loosen the bark.
Bud With Wood Attached
Cut a bud from bud stick (A) which includes a thin piece of attached wood (B). Start the bud under the flaps of bark and lead it down by the handle (see D and E in figure 6).
TyingUse rubber strips, electrician's tape, or adhesive tape to tie the bud. Wrap and tie tightly, but be sure you do not cover the bud (see F in Figure 6).
AftercareCut the tie before it binds too tightlythat is, in two or three weeks. Cut on the side away from the bud. Rubber strips need not be cut. The bud should remain dormant until the following spring. Cut off the stock above the bud as soon as the bud starts growing.
Do not permit any shoot growth.
After the second year, remove all extra growth from the stock, that is, keep only the bud grafted shoots. When two or more buds grow, all can be used, but one is usually enough to produce a new branch.
Bud With Wood Removed
As illustrated in Figure 7, cut from A well under the bud to B. Remove the knife and rock the blade just through the bark at B. Grasp the bark between your thumb and finger and pinch the bark with attached bud (C) free from the wood (D). If the bud stick is fresh and in good condition, you will be successful after a few tries.
Figure 7. Bud with wood removed.
Buds which have the sliver of wood removed have a complete cambium surface exposed to meet the cambium of the stock and sometimes result in better growth, but they are not rigid enough to handle easily. Buds with wood attached are easier to handle and usually give good results. (See above, for "Tying" and "Aftercare" of the bud.)
When the bark of a tree is removed (girdled) completely around the trunk, that part of the tree above the damaged area will die. Even though completely girdled, some trees may leaf out and remain alive for one season, but both the top and root will die the second year unless shoots have been produced below the girdled areas.
Girdling can be caused by rodents, which damage many fruit trees each year. Occasionally a tree may only appear to be girdled if the gnawing has not gone through the bark to the wood. Sometimes the girdled area extends less than halfway around the trunk, and such injuries are protected from drying out, new bark will grow from the cambium. As soon as you discover an injury, cover it with an asphalt grafting compound.
Rabbit damage is usually some distance above the ground or snow line. These animals cut off twigs and pull off bark in shreds. Mice work near the ground out of sight under grass or snow. They usually begin at one spot and enlarge it. Pocket gophers gnaw off roots below the ground. Trees hurt in this way often tip over and cannot be repaired.
The following supplies are necessary to repair girdled trees:
- A sharp knife, such as a good jackknife
- Small nails for tacking scions to the tree
- A light hammer
- A nail set
- A saw for trimming old thick bark
- A shovel or trowel if damage is below the ground
- A heavy scrub brush for cleaning excavated bark
- Dormant or fresh cut scions for bridges
- Asphalt grafting compound or asphalt wound dressing
ScionScions for apple trees may be taken from any hardy cultivar of apple or crab apple. Pear scions must be used for pear, plum for plums, and so on. Old trees rarely produce good scion wood unless they were pruned well the previous year. If 1-year old-wood is not available, 2-year wood may be used. If you can anticipate the need, you should cut the scions before any growth begins. Keep them in moist and cool storage. You may cut the scions, fresh as needed, if you bridge promptly before shoot growth begins.
Small TreeApple and pear trees under 2 inches in diameter are too small to bridge. The swaying of such small trunks by strong winds will dislodge the scions. If the tree is under 1 inch, it is best to saw it off just below the girdle, then cover the cut with asphalt wound dressing or grafting compound. Shoots of the same cultivar probably will grow out from above the place the tree originally had been grafted. Trees between 1 and 2 inches can best be treated by cutting or sawing them off below the injury in the spring and placing scions in the stubs by cleft grafting. Cherry and plum trees usually are not bridge grafted successfully. If they are only 2 or 3 years old, cut off below the injury and a new shoot will grow out from above the place where the tree originally had been grafted.
How To Bridge GraftBridge grafting is done in the spring after growth has started when the bark of the tree to be repaired will lift readily (slip) from the woodusually between April 15 and May 15.
The first step is to trim the bark of the girdled trees both above and below the girdle. Cut back damaged or frayed bark an inch or so to sound bark. The edges should be clean and smooth. Scrape down old rough bark to live bark.
Two methods of setting scions are used: (1) the L-cut, best for trees with thin bark, and (2) inlay, for trees with thick bark.
To make the L-cut, start at the edge of live bark and cut a slit about 2 inches long in the bark below the girdle (left side in Figure 8). Lift the edges with a dull smooth tool. Such a tool can readily be shaped from hardwood or a piece of plastic. The rat tail of a comb is good for this purpose. Do not use the scion to lift the bark.
Figure 8. Two methods of bridge grafting (L-cut on the left and inlay on the right) are shown. The scion on the left is inserted under the bark at each end; the scion on the right is laid in a groove at each end.
Prepare a second slit at the upper side of the girdle directly above the first.
Shape the scion on the lower end and measure against the girdle to determine the length of the scion. Shape the upper end of the scion to a definite taper with a longer flat surface next to the tree. Slip the ends under the bark, nail them in position and nail down the flaps of bark. In nailing either scion or bark, use care to avoid crushing the bark. A nail set will help to avoid injury to the bark.
The inlay method (right side of Figure 8) is the best bridge grafting technique. In fact, it is a necessity for a short span. Select a curved scion to make an inlay bridge. Measure the distance to be spanned and make the scion long enough to extend 1½ to 2 inches beyond the girdle at each end. Cut a straight, smooth face on each end.
Place a nail in each end. Tack this lightly to the tree bark to mark the place. Mark around each end on the bark to get the exact size of the scion. Remove the scion, cut to the wood on the marks, and lift out the piece of bark. Then fit the scion in the channels in the bark and nail carefully. One nail is usually enough.
In either grafting method, place a scion every 1½ to 2 inches around the tree.
There is a third method to insert scions in bridge grafting, as shown in Figure 9. Little or no trimming is done to the bark that borders the damaged area. This is a little less tidy and it requires somewhat longer scions, but it is quicker and equally effective.
Figure 9. A quick way to bridge girdled trees.
Scions are cut and inserted essentially the same as in Figure 8.
Covering and careWhen all the scions are in place, the graft unions should be covered with grafting compound. Note that the entire girdled surface should be covered and more than one coat may be necessary.
In bridge grafting, after the scions begin to grow, it is important that all shoots or leafy growth be cut or rubbed off the scions.
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