Shield Budding

Publication 753 - Revised by John W. Jett (1997)

Grafting is a form of vegetative reproduction by which new plants having the same characteristics as the parent plant may be obtained. Grafting methods include whip grafting, saddle grafting, cleft grafting, approach grafting, and budding. Some methods are simple, requiring no special ability. Others, however, may require greater dexterity.

Shield budding, also known as "T" budding, does require a certain amount of care, especially in obtaining the scion or bud. Budding, also know as bud grafting, differs from other methods of grafting in that only one bud is utilized. Other forms of grafting require a short piece of stem containing several buds and in some cases a few leaves. Budding is best accomplished when the bark is loose. This could be anytime that the plant is actively growing from early spring (March) until early fall (September). In West Virginia, fall budding is recommended.

Fall Budding (Late July to Early September)

Collecting Bud Sticks

Bud sticks or shoots from plants to be propagated should be collected from the current season's growth. These shoots should have well-developed growth (vegetative) buds. Growth buds are distinguished from flower buds in that they are small, slender, and pointed. Flower buds are larger, rounded and plump. Basal and middle buds on the bud stick are the best. Buds from succulent terminal growth should be discarded.

Cut off the foliage leaving about inch of the petiole (leaf stem) as shown in Figure 2. The petiole will be a means by which the bud can be handled and later can indicate whether or not the bud has successfully united with the understock. Bud sticks should be freshly cut each day and not allowed to become dry.

Selecting Understock

The understock, sometimes called rootstock, used in budding is generally seedlings grown for budding purposes. The understock should be closely related to the plants to be grafted. For example, apples should be grafted on apples or crabapples, etc. The understock should be to 1 inch in diameter, free of insects and diseases and hardy. They should have a good root system. They may be field or container grown. Container grown seedlings make good understock as they may be moved to protected areas during severe winter conditions, especially during the first winter after budding.

Steps in Budding

At a smooth place on the understock, two to ten inches above the ground, make a vertical cut about one inch long. Then make a horizontal cut about inch long at the top of the vertical cut. This will result in a "T" shaped cut in the bark as shown in Figure 1a. Carefully lift the flaps of bark at the top of the horizontal cut as shown in Figure 1b.

The next step is to remove the bud from the bud stick. To remove the bud begin a cut about inch below the bud and make a shallow upstem cut and continue to about inch above the bud (Figure 2a). Make a horizontal cut above the bud and remove the shield containing the bud (Figure 2b). The small amount of wood under the bud may be left intact or the bark containing the bud may be gently peeled from the wood.

Next, insert the bud shield into the incision in the understock as illustrated in Figure 3a. Wrap the union with a rubber budding strip, raffia, or string. Do not cover the bud (Figure 3b). In two to three weeks a successful union will be indicated by the leaf petiole cleanly dropping from the inserted bud. If string or raffia is used to wrap the union, it should be cut off or it will restrict the union. Rubber budding strips deteriorate naturally.

The inserted buds should not begin growth until the following spring. If for some reason the buds do not "push out," they may have been winter killed. Container grown materials may be moved into a protected area. If they are field grown, mound soil over the bud.

In the spring, following budding, cut off the understock to just above the inserted bud. (See Figure 4.) This will force the bud into growth. Make a slanted cut, slanted away from the bud as shown in Figure 4. Any latent buds on the understock should be removed as soon as they appear. The plants may need to be inspected several times in order to remove all these undesirable buds.

Spring budding (March and April)

Spring budding is similar to the fall budding just described except the bud sticks are collected when the plants are dormant. The bud sticks are then stored in damp peat moss or similar material or sealed in a polyethylene bat to keep from drying. A home refrigerator is ideal for storing the bud sticks. Maintain a temperature of 32oF to 40oF (0oC to 4oC). Budding is then done in early spring as soon as active growth of the understock begins and the bark is easily separated from the wood.

About two weeks after budding, when the bud union has healed, the top of the understock must be cut off above the bud as previously described for fall budding. This will force the inserted bud into active growth. As latent buds on the understock begin to grow, they should be removed.

June Budding (Late May to Early June)

June budding should be confined to areas with a relatively long growing season, such as California or Florida, as the buds are forced into active growth the same season. The bud sticks are collected in late May or early June and should be of the current season's growth. Growth buds should have developed by this time. Again, only basal or mid-stem buds should be used. The bud sticks should not be stored but should be used as soon as possible after collecting. The bud should be inserted as described in fall budding. A number of leaves, at least three or four, should be retained on the understock below the inserted bud. After the petiole drops, healing should have occurred, and the top of the understock should be cut back two to five inches above the inserted bud retaining several leaves above and below the bud. About two weeks after healing, the understock should be cut back to the inserted bud. Shoots on the understock below the bud should be removed. When the bud has grown eight to ten inches, all shoots and leaves from the understock should be removed.

Shield budding is not difficult, but care should be taken in each step to assure a successful union. The growing season in West Virginia is not sufficiently long for June budding; therefore fall budding is recommended with spring budding as an alternative. Regardless of the time of the year budding is done, success is determined by the care it receives afterwards. Two important factors should be kept in mind. First, the shoots of latent buds below the graft should be removed. Second, the new growth from the inserted bud should be staked if necessary. This lessens the possibility of the graft being broken in high winds. Otherwise, general maintenance practices should be observed.