The grafting knife described previously can be purchased with a pointed, blunt end useful in inserting the bud piece. Other tools have been devised to make the budding technique faster and easier. These include an assortment of double-bladed knives for patch budding that permit simultaneous parallel cuts on opposite sides of the bud to be made in a single stroke. The bark patch removed from the stock plant will be of a similar size to the bud patch (Figure 14-8). The result is a tighter fit and more rapid healing.
Methods of Budding
There are several different methods of budding. Some require actual removal of bark from the stock. Others require only an incision into the bark permitting the bud to be slipped in behind it. Following are some of the methods.
figure 14-9. Steps in making a T-bud (Delmar/Cengage Learning)
T-budding The most widely used method of budding, T-budding, derives its name from the shape of the incision made in the bark of the stock plant (Figure 14-9). It is most adaptable to young, thin-barked nursery stock up to an inch in diameter. It is the major propagation technique used in the commercial production of roses. The bud is cut from a slipping budstick as a shield-shaped piece. The cut should be shallow, just beneath the bark, avoiding the wood as much as possible. The bud shield should be cut from an inch above the bud to half an inch below it. Using the thumb, a gentle sideward push separates the bud shield from the wood. The stock is prepared with a one-inch long vertical cut through the bark on a smooth internodal section of stem. A horizontal cut across the top completes the T-incision. The blunted end of the budding knife lifts the stock’s bark and the bud shield is inserted. When the upper edge of the bud shield matches the top of the T-incision, the bark flaps are closed around, but not over, the bud. Then the bud graft is tied, usually with a rubber budding strip. The strip ensures a tight fit of stock and scion and prevents drying. After several weeks, the rubber strips will decompose and fall away. Waxing is not necessary. In some parts of the country, the T-incision is reversed to keep out rain that could promote rotting of the bud. This is termed inverted T-budding.
Patch-budding Using rootstocks and budsticks that are nearly the same size (about an inch in diameter), a rectangular patch of bark is removed from both the stock and the scion (Figure 14-10). The scion patch contains the bud that will be the shoot of the new plant. The special tools described earlier help to keep both patches the same size. The most appropriate use of patch budding is with a stock plant that has thick bark and a scion plant whose budsticks have thin bark. With heavy bark, a T-bud graft does not fit tightly enough. The closer the fit is, the better are the chances of a successful graft union. Following insertion of the scion patch into the stock plant, the union is wrapped, leaving the bud uncovered.
I-budding This method is a combination of the techniques thus far described. The scion is prepared by cutting a patch from the budstick (Figure 14-11). The stock does not have a patch of bark removed;
figure 14-10. Steps in making a patch bud (Delmar/Cengage Learning)
figure 14-11. Steps in making an I-bud (Delmar/Cengage Learning) instead, an I-shaped cut is made into the bark. The two horizontal cuts and one vertical cut create two flaps of bark. These can be lifted up and the bud patch slipped beneath. Following insertion of the bud patch, and after ensuring that stock and scion meet, the graft should be tied.
Chip budding When either the season of the year or environmental conditions result in a nonslipping bark condition, it is still possible to propagate some plants by budding. Chip budding unites a chip of wood containing a bud from the scion with a stock plant that has had a comparably sized chip removed from an internodal area near the base (Figure 14-12). The technique works best with small wood up to an inch in diameter. The chips are removed with two downward cuts that intersect. With the scion, one cut begins one-half inch above the bud and proceeds downward and inward to a point about one-quarter inch beneath the bud. The other cut is beneath the bud, downward and angled sharply
figure 14-12. Steps in making a chip bud (Delmar/Cengage Learning)
inward to intersect the longer cut from above. The cut into the stock is made the same way. As with all bud grafting, the closer the two chips are in size, the better the chance of rapid healing of the union.
Follow-up Regardless of which budding technique is used, the followup procedures are the same. If budded in the fall, the shoots of the stock may be retained until the following spring. Then they are cut off above the graft union as soon as the buds begin to break dormancy. If budded in the spring, the stock can be cut back as soon as the graft union is established, in ten to fourteen days. Summer budding usually results in dormant scion buds that do not break until the following spring, even though the union has been established. They can be treated in the same manner as fall-budded plants.