What is the graft?

Learn to Graft Your Favorite Plants

Grafting is the mad-scientist way of propagating your plants. Slice a piece from one plant and splice it onto another. Cool! Let’s see how.

Many of the plants at your local garden center may be grafted. For example, many hybrid roses are grafted so they grow on the roots of a tougher variety of rose. This helps them stand up to tough conditions and bloom more vigorously. Likewise, most fruit trees are grafted onto smaller variety’s roots. This keeps the trees more compact and vigorous. Plants trained as standards, or tree forms, are also usually grafted onto the trunk of another plant.

Somebody really released their inner Dr. Frankenstein when they grafted several varieties on the same tree, so you have an apple tree that produces ‘Red Delicious’ and ‘Golden Delicious’ fruits. This is how we got the famous “fruit-cocktail tree.”

Once you’ve created healthy seedlings, learn how to transplant them to your yard.

Step 1: Collect a Branch The best time to graft is late winter — December to February, depending on where you live. Start by taking a fresh, 3- to 4-inch-long shoot with one or two buds. Select plants that are closely related; for example, graft an apple onto another variety of apple or a pear on another variety of pear. Or, try grafting almond, apricot, or plum branches on a peach tree. You cannot graft unrelated plants — such as a rose and a persimmon — onto one another.

Step 2: Prepare the Rootstock The rootstock is the plant you’ll be growing your new branch onto. Carefully make a 2-inch sloping diagonal cut through a stem about 6 inches above the ground. Next, make a 1/2-inch-deep cut straight down the stem, about a third of the way down your sloping cut.

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Step 3: Match the Branch Make a sloping diagonal cut on the bottom of the branch you’ll place on the rootstock. Because you’re splicing this branch on the main plant, the sloping cut needs to be the same size and angle as the cut you made on the main plant’s stem. Then about a third of the way down the slope of your branch, make a 1/2-inch-deep cut up the branch to match the one on the rootstock.

Step 4: Bring them Together Carefully force the branch to slide onto the stem, lining up the cuts together. Make sure the two line up as closely as possible. Then wrap the joined area with twine and cover with grafting wax (available at your local garden center or nursery) to keep the tissue from drying out. If the graft takes, your new branch will begin to grow in spring.

Grafting useful for making unique plant forms

Grafting is a centuries-old craft in which a person takes pieces from two or more different plants and grafts them together so they grow as one plant. The grafting process is performed because it brings multiple positive traits from separate plants into a single plant. It’s a technique that can be used to create plants with improved disease resistance and hardiness, increased yields or unique physical forms, such as topiaries, standards, weeping branches and compact growth habits.

Though there are many different types of grafting, in its simplest form, grafting attaches the shoot system (the scion) of one plant to the root system (the rootstock) of a separate plant. The two are grafted together in a fairly simple procedure, and once the graft union has healed, the two plants grow as one. In most cases, the scion and rootstock must be from the same species (or, sometimes, the same family) in order for them to be compatible with each other and for the graft union to be successful. In other words, you can’t graft a juniper with an oak tree. But, you can graft an apricot with a peach tree because they’re in the same stone-fruit family.

Nurserymen and women sometimes use grafting to create dwarf or compact plants by selecting and using a specific root stock with dwarfing traits. Then, they graft the shoot system of a full-sized compatible variety of that plant on top of the root stock. The dwarfing trait in the rootstock is then transferred to the shoot system, yielding dwarf fruit trees, some types of dwarf evergreens, or other compact plants.

Grafting is quite common among fruit and ornamental trees, especially those with unique or specialized forms. For example, many weeping trees are created by grafting a pendulous shoot system onto a straight-trunked variety of the same plant, and some Japanese maples and fruit trees may be grafted onto different rootstocks in order to improve their winter hardiness. Novelty pom-pom bushes are often created through grafting as well.

Another way grafting is used is to make “standards.” A “standard” is a particular artificially created form of a plant — typically a shrub or a woody sub-shrub — where the shoot system is perched atop a section of tall, straight stem. “Standards” look like lollipop plants. Rose and evergreen standards are most common, but you’ll sometimes come across heliotrope, plumbago and even hydrangea standards. Standards are made by grafting a section of tall, straight stem onto the root system (making it an inter-stock). Then, on top of that straight stem is grafted a portion of a regular shoot system. The plant is then pruned and trained to form a ball on top of the straight stem (see photo).

Grafting is useful only for the generation of plants on which it was performed. The improvements or dwarfing traits made through grafting are not carried to the next generation via saved seeds or even by taking cuttings of the plant. It’s just for a single generation. Still, grafting can create some pretty unique plants with desirable traits for the gardener.

  • Horticulturist Jessica Walliser is the author of several gardening books, including “Attracting Beneficial Bugs to Your Garden,” “Good Bug, Bad Bug,” and her newest title, “Container Gardening Complete.” Her website is jessicawalliser.com. Send your gardening or landscaping questions to or The Good Earth, 622 Cabin Hill Drive, Greensburg, PA 15601.

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    Grafting and Budding Nursery Crop Plants

    Grafting

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    When to Graft
    Unlike budding, which can be performed before or during the growing season, most grafting is done during winter and early spring while both scion and rootstock are still dormant. Containerized plants may be moved indoors during the actual grafting process; after grafting, these plants are placed in protected areas or in unheated overwintering houses. Field-grown stock, of course, must be grafted in place. Some deciduous trees are commonly grafted as bare rootstock during the winter and stored until spring planting. Indoor winter grafting is often referred to as bench grafting because it is accomplished at a bench.
    Selecting and Handling Scion Wood
    The best quality scion wood usually comes from shoots grown the previous season. Scions should be severed with sharp, clean shears or knives and placed immediately in moistened burlap or plastic bags. It is good practice during the harvesting of scions and the making of grafts to clean the cutting tools regularly. This may be done by flaming or immersing them in a sterilizing solution. Isopropyl (rubbing) alcohol also works well as a sterilant, although it evaporates quite readily. An alternative sterilizing solution may be prepared by mixing one part household bleach with nine parts water (by volume). However, this bleach solution can be highly corrosive to certain metals.

    For best results, harvest only as much scion wood as can be used for grafting during the same day. Select only healthy scion wood that is free from insect, disease, or winter damage. Be sure the stock plants are of good quality, healthy, and true to type. Scion wood that is frozen at harvest often knits more slowly and in lower percentage. If large quantities of scion wood must be harvested at one time, follow these steps:

    • Cut all scions to a uniform length, keep their basal ends together, and tie them in bundles of known quantity (for example, 50 scions per bundle).
    • Label them, recording the cultivar, date of harvest, and location of the stock plant.
    • Wrap the base of the bundles in moistened burlap or sphagnum, place them in polyethylene or waterproof paper bags, and seal the bags.
    • Store the bundles for short periods, if necessary, either iced down in insulated coolers or in a commercial storage unit at 32° to 34°F.
    • Never store scions in refrigerated units where fruits or vegetables are currently kept or have been stored recently. Stored fruits and vegetables release ethylene gas, which can cause woody plant buds to abort, making the scions useless.
    • Keep the scions from freezing during storage.

    NOTE: In grafting, as well as budding, the vascular cambium of the scion or bud must be aligned with the vascular cambium of rootstock. In woody plants the cambium is a very thin ribbon of actively dividing cells located just below the bark. The cambium produces conductive tissue for the actively growing plant (Figure 1). This vascular cambium initiates callus tissue at the graft and bud unions in addition to stimulating tissue growth on the basal ends of many vegetative cuttings before they have rooted.

    Types of Grafts
    Nurserymen can choose from a number of different types of grafts. This section describes only those basic types of grafts used on nursery crop plants.
    Cleft Graft
    One of the simplest and most popular forms of grafting, cleft grafting (Figure 2), is a method for top working both flowering and fruiting trees (apples, cherries, pears, and peaches) in order to change varieties. Cleft grafting is also used to propagate varieties of camellias that are difficult to root. This type of grafting is usually done during the winter and early spring while both scion and rootstock are still dormant. Cleft grafting may be performed on main stems or on lateral or scaffold branches.
    The rootstock used for cleft grafting should range from 1 to 4 inches in diameter and should be straight grained. The scion should be about 1⁄4-inch in diameter, straight, and long enough to have at least three buds. Scions that are between 6 and 8 inches long are usually the easiest to use.

    • Preparing the Rootstock. The stock should be sawed off with a clean, smooth cut perpendicular to the main axis of the stem to be grafted. Using a clefting tool wedge and a mallet, make a split or “cleft” through the center of the stock and down 2 to 3 inches. Remove the clefting tool wedge and drive the pick end of the tool into the center of the newly made cleft so that the stock can be held open while inserting the scion.
    • Preparing the Scion. In cleft grafting, one scion is usually inserted at each end of the cleft, so prepare two scions for each graft. Select scions that have three or four good buds. Using a sharp, clean grafting knife, start near the base of the lowest bud and make two opposing smooth-tapered cuts 1 to 2 inches long toward the basal end of the scion. Cut the side with the lowest bud slightly thicker than the opposite side. Be sure the basal end of the scion gradually tapers off along both sides.
    • Inserting the Scion. Insert a scion on each end of the cleft, with the wider side of the wedge facing outward. The cambium of each scion should contact the cambium of the rootstock.
    • Securing the Graft. Remove the clefting tool from the cleft so that the rootstock can close. Pressure from the rootstock will hold the scions in place. Thoroughly seal all cut surfaces with grafting wax or grafting paint to keep out water and prevent drying. If both scions in the cleft “take,” one will usually grow more rapidly than the other. After the first growing season, choose the stronger scion and prune out the weaker.

    NOTE: The temperature of grafting wax is critical. It must be hot enough to flow but not so hot as to kill plant tissue. Recently, paint-like sealants have replaced wax in many areas because they are easier to use and require no heating.

    Bark Graft
    Bark grafting (Figure 3) is used primarily to top work flowering and fruiting trees. In contrast to cleft grafting, this technique can be applied to rootstock of larger diameter (4 to 12 inches) and is done during early spring when the bark slips easily from the wood but before major sap flow. The rootstock is severed with a sharp saw, leaving a clean cut as with cleft grafting.

    • Preparing the Stock. Start at the cut surface of the rootstock and make a vertical slit through the bark where each scion can be inserted (2 inches long and spaced 1 inch apart).
    • Preparing the Scion. Since multiple scions are usually inserted around the cut surface of the rootstock, prepare several scions for each graft. Cut the base of each scion to a 11⁄2- to 2-inch tapered wedge on one side only.
    • Inserting the Scion. Loosen the bark slightly and insert the scion so that the wedge-shaped tapered surface of the scion is against the exposed wood under the flap of bark. Push the scion firmly down into place behind the flap of bark, replace the bark flap, and nail the scion in place by driving one or two wire brads through the bark and scion into the rootstock. Insert a scion every 3 to 4 inches around the cut perimeter of the rootstock.
    • Securing the Graft. Seal all exposed surfaces with grafting wax or grafting paint. Once the scions have begun to grow, leave only the most vigorous one on each stub; prune out all the others. Bark grafts tend to form weak unions and therefore usually require staking or support during the first few years.

    Side-Veneer Graft
    At one time the side-veneer graft (Figure 4) was a popular technique for grafting varieties of camellias and rhododendrons that are difficult to root. Currently, it is the most popular way to graft conifers, especially those having a compact or dwarf form. Side-veneer grafting is usually done on potted rootstock.

    • Preparing the Stock. Rootstock is grown in pots the season before grafting, allowed to go dormant, and then stored as with other container nursery stock. After exposure to cold weather for at least six weeks, the rootstock is brought into a cool greenhouse for a few days before grafting takes place to encourage renewed root growth. The plant should not be watered at this time.
      Make a shallow downward cut about 3⁄4-inch to 1 inch long at the base of the stem on the potted rootstock to expose a flap of bark with some wood still attached. Make an inward cut at the base so that the flap of bark and wood can be removed from the rootstock.
    • Preparing the Scion. Choose a scion with a diameter the same as or slightly smaller than the rootstock. Make a sloping cut 3⁄4-inch to 1 inch long at the base of the scion. (Use the bark grafting technique shown in (Figure 3).
    • Inserting the Scion. Insert the cut surface of the scion against the cut surface of the rootstock. Be certain that the cambia contact each other.
    • Securing the Graft. Hold the scion in place using a rubber grafting strip, tape, or grafting twine. Seal the entire graft area with warm grafting wax or grafting paint. Remove the rubber or twine shortly after the union has healed. Never allow the binding material to girdle the stem.

    Splice Graft
    Splice grafting (Figure 5) is used to join a scion onto the stem of a rootstock or onto an intact rootpiece. This simple method is usually applied to herbaceous materials that callus or “knit” easily, or it is used on plants with a stem diameter of 1⁄2-inch or less. In splice grafting, both the stock and scion must be of the same diameter.

    • Preparing the Stock and Scion. Cut off the rootstock using a diagonal cut 3⁄4-inch to 1 inch long. Make the same type of cut at the base of the scion.
    • Inserting the Scion. Fit the scion to the stock. Wrap this junction securely with a rubber grafting strip or twine.
    • Securing the Graft. Seal the junction with grafting wax or grafting paint. Water rootstock sparingly until the graft knits. Over watering may cause sap to “drown” the scion. Be sure to remove the twine or strip as soon as the graft has healed.

    Whip and Tongue Graft
    The whip and tongue technique (Figure 6) is most commonly used to graft nursery crops or woody ornamentals. Both the rootstock and scion should be of equal size and preferably no more than 1⁄2-inch in diameter. The technique is similar to splice grafting except that the whip on the rootstock holds the tongue of the scion in place (and vice versa). This leaves both hands free to wrap the joint.

    For the whip and tongue graft, make similar cuts on both the stock and scion. These cuts should be made with a single draw of the knife and should have a smooth surface so that the two can develop a good graft union. Up to this point, rootstock and scion are cut the same as for a splice graft.

    • Preparing the Stock and Scion. Cut off the stock using a diagonal cut. The cut should be four to five times longer than the diameter of the stock to be grafted. Make the same kind of cut at the base of the scion.
      Next, place the blade of the knife across the cut end of the stock, halfway between the bark and pith (on the upper part of the cut surface). Use a single knife stroke to draw the blade down at an angle through the wood and pith. Stop at the base of the initial diagonal cut. This second cut must not follow the grain of the wood but should run parallel to the first cut.
    • Inserting the Scion. Prepare the scion in the same way. Fit the scion into the rootstock so that they interlock whip and tongue. Be certain that the cambia are aligned.
    • Securing the Graft. Wrap the junction with a grafting strip or twine, and seal it with grafting wax or grafting paint. Never allow the binding material to girdle the stem.

    Saddle Graft
    Saddle grafting (Figure 7) is a relatively easy technique to learn and once mastered can be performed quite rapidly. The stock may be either field-grown or potted. Both rootstock and scion should be the same diameter. For best results, use saddle grafting on dormant stock in mid- to late winter. Stock should not be more than 1 inch in diameter.

    • Preparing the Stock. Using two opposing upward strokes of the grafting knife, sever the top from the rootstock. The resulting cut should resemble an inverted V, with the surface of the cuts ranging from 1⁄2-inch to 1 inch long.
    • Preparing the Scion. Now reverse the technique to prepare the base of the scion. These cuts on the rootstock and scion must be the same length and have the same slope so that a maximum amount of cambial tissue will make contact when the two halves are joined.
    • Inserting the Scion. Place the V-notched scion onto the saddle of the rootstock. If rootstock and scion are the same diameter, cambial alignment is easier; otherwise adjust as needed.
    • Securing the Graft. Wrap the graft with a grafting twine, tape, or strip, then seal it with grafting wax or grafting paint.

    All of the preceding techniques are used to top work horticultural crops for a particular purpose. Occasionally, however, grafting is used to repair injured or diseased plants. Two common techniques available for this purpose are bridge grafting and inarch grafting.

    Bridge Graft
    Bridge grafting (Figure 8) is used to “bridge” a diseased or damaged area of a plant, usually at or near the base of the trunk. Such damage commonly results from contact with grading or lawn maintenance equipment, or it may be caused by rodents, cold temperatures, or disease organisms. The bridge graft provides support as well as a pipeline that allows water and nutrients to move across the damaged area.

    Bridge grafts are usually done in early spring just before active plant growth begins. They may be performed any time the bark on the injured plant “slips.”

    • Preparing the Scion. Select scions that are straight and about twice as long as the damaged area to be bridged. Make a 11⁄2- to 2-inch-long tapered cut on the same plane at each end of the scion.
    • Preparing the Stock. Remove any damaged tissue so the graft is on healthy stems. Cut a flap in the bark on the rootstock the same width as the scion and below the injury to be repaired. Gently fold the flap away from the stock, being careful not to tear the bark flap.
    • Inserting the Scion. First, insert and secure the scion below the injury; push the scion under the flap with the cut portion of the scion against the wood of the injured stem or trunk. Then go back and insert and secure the scion above the injury following these same steps. Push the scion firmly into place. Pull the flap over the scion and tack it into place as described for bark grafting (Figure 3).
      When grafting with young stems that may waver in the wind, insert the scions so that they bow outward slightly. Bridge grafts should be spaced about 3 to 4 inches apart across the damaged area.
    • Securing the Graft. Secure all graft areas with warm grafting wax or grafting paint. During and after the healing period, remove any buds or shoots that develop on the scions.

    Inarch Graft
    Inarching, like bridge grafting, is used to bypass or support a damaged or weakened area of a plant stem (Figure 9). Unlike bridge grafting, the scion can be an existing shoot, sucker, or watersprout that is already growing below and extending above the injury. The scion may also be a shoot of the same species as the injured plant growing on its own root system next to the main trunk of the damaged tree. With the inarching technique, the tip of the scion is grafted in above the injury using the same method as for bark or bridge grafting.

    Figure 1. Cross section of a woody plant stem.

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    Figure 1. Cross section of a woody plant stem.

    Figure 2. Cleft graft.

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    Figure 2. Cleft graft.

    Figure 3. Bark graft.

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    Figure 3. Bark graft.

    Figure 4. Side veneer graft.

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    Figure 4. Side veneer graft.

    Figure 5. Splice graft.

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    Figure 5. Splice graft.

    Figure 6. Whip and tongue graft.

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    Figure 6. Whip and tongue graft.

    Figure 7. Saddle graft.

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    Figure 7. Saddle graft.

    Figure 8. Bridge graft.

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    Figure 8. Bridge graft.

    Figure 9. Inarch graft.

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    Figure 9. Inarch graft.

    What is Grafting? Uses in Addition to Plant Propagation

    What is Grafting in Plants?

    In crop farming or crop agriculture, grafting is most commonly referred to as an artificial, vegetative method of plant propagation. However, as a technique or procedure, it has many other uses. The term is also applied in animals and in humans as in skin grafting.

    Grafting converted this single-trunked san francisco (Codiaeum variegatum) into a plant with shoot consisting of two leaf variants

    Plant grafting is a procedure in which parts of plants are joined together with the ultimate intention of making them unite and continue growing as one plant. A grafted plant, therefore, is a composite of parts derived from two or more plants.

    Grafting generally applies to the dicots and to the gymnosperms because of the presence of a continuous vascular cambium between the xylem and the phloem. But in the monocots that have no vascular cambium, successful grafts are rare and difficult.

    Two terms are common in grafting: rootstock and scion. These terms are always used in reference to what is grafting rather than in other methods of plant propagation.

    The rootstock, also called understock or simply stock, is the lower part having roots and usually consists also of a stem that is to become the lowermost part of the shoot of the grafted plant. The rootstock provides anchorage as well as support to the upper parts of the plant.

    The scion, or cion, is the upper part that is joined to the rootstock and is the main component of the plant shoot when the plant is fully developed. It usually consists of the primary stem (trunk) and branches except the portion that belongs to the rootstock. The scion determines the characteristics of the plant as to leaves, flowers, fruits and seeds, and thus needs to be chosen with care.

    In plant propagation by grafting, the scion to be joined to the rootstock consists of a portion of stem, usually small twigs, with multiple number of buds. The apical bud is usually included, but other species can be readily grafted using scions with only axillary buds. Where the scion consists of a single bud, the grafting method is especially termed budding.

    What is Grafting: Method of Plant Propagation and Other Uses

    1. Plant Propagation. In some plant species and varieties, grafting is the better method of mass propagation where uniformity in plant characteristics is desired. This is so in plants in which other asexual methods are ineffective. It is also employed where other methods do not allow the production of a big number of planting materials in the shortest time possible. While budding has the potential of producing more clones from a single mother plant because scions with a single bud are used, the growth of the scion is slow and it will take more time to produce the right sizes of budded plants for outplanting. Plant cuttings generally exhibit the same growth rate.

    2. Producing Composite Plants with Rootstocks Having Special Characteristics. Desirable scions can be grafted on rootstocks that are adapted to certain conditions such as heavy, wet, or dry soils, or resistant to soilborne pests and diseases. There are rootstocks also that will enhance the vigor or induce dwarfing of the grafted plant. In citrus, some rootstocks favor the production of fruits with better size and quality (Hartmann and Kester 1975).

    In general, the compatibility of the rootstock and scion that leads to successful union depends on how close they are in their taxonomic classification. The possibility of a successful union is more ensured among plants within the same species. But intergeneric grafting is now widely practiced in plant propagation to take advantage of more adapted and disease resistant rootstocks. Examples are the eggplant (Solanum melongena) and upo or bottle gourd (Lagenaria siceraria), as rootstocks, with tomato (Lycopersicon esculentum) and watermelon (Citrullus lanatus), respectively. Eggplant and tomato belong to the family Solanaceae while bottle gourd and watermelon are both members of the family Cucurbitaceae.

    Old jokes in relation to what is grafting: (1) Q: Can bamboo and banana be grafted? Ans: Yes, as in banana cue (a bamboo stick is used to pierce a fried sweetened plantain for easy handling). (2) Q: Can bamboo and coconut be grafted? Ans: Yes, to produce tuba or coconut toddy (a segment of bamboo culm is traditionally used as a container into which the coconut inflorescence that is sliced daily is inserted to collect the sweet coconut sap that exudes).

    3. Conversion of Adult Trees to Desirable Types. Large, mature trees can be converted to another species or variety having desirable characteristics by topworking (or top-grafting). Regrafting of the top with scions obtained from “carabao” mango has been applied in mango trees that have started fruiting but found to belong to an inferior variety . Intervarietal conversion is also resorted in association with the rejuvenation of old and unproductive coffee. Likewise, some dioecious trees can be converted from male to female to make them productive or from female to male to ensure supply of pollen for the entire orchard.

    4. Producing Botanical Curiosities. Special types of plants can be produced by grafting two or more scions with different characteristics on the same rootstock. For example, a mango tree can be topworked in a manner that different branches will bear different fruit types. A croton or san francisco (Codiaeum variegatum) can also have a foliage with different leaf types and variegation.

    5. Artistic Enhancement. In bonsai, a tree that lacks an essential branch at certain part of the trunk, or branch, can have one by grafting thereon a scion, usually by side or approach grafting. This is a strategy applied in creating fine bonsai trees that requires a substantial understanding on what is grafting and its various techniques.

    6. Repairing Damaged Trees. Tree plants with damaged portions of the trunk are common where there are goats and carabaos. Occasionally, damage to trunks and branches is also caused by fire, insects, diseases, mechanical impact, and mishandling of tools. These damaged parts can be repaired and saved by inarching or bridge-grafting.

    7. Additional Anchorage and Support. In places that are prone to strong winds, it is advantageous if tree crops are anchored well to the ground. Lodging can be prevented or minimized by producing tripods or multiple-trunk trees by inarching. Similarly, weak branches and split trunks can be prevented from breaking by brace grafting.

    8. What is Grafting: Indexing for Virus Diseases. Some plants have strong tolerance to virus diseases so that even if the disease is present, they exhibit little or no symptom. To identify plants that may carry the virus, scions or buds from such plants are grafted onto a healthy, susceptible indicator plant. If the suspected plant from which the scion or bud is derived is infected, the virus will be transmitted and the indicator plant will show the symptoms of the disease (Hartmann and Kester 1975).

    REFERENCE

    HARTMANN HT, KESTER DE. 1975. Plant Propagation: Principles and Practices. 3rd ed. New Jersey: Prentice Hall Inc. 662 p.

    (Ben G. Bareja May 2011)

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    Graft

    Techniques

    The basic technique in grafting consists of placing cambial tissues of stock and scion in intimate association, so that the resulting callus tissue produced from stock and scion interlocks to form a living continuous connection. Stock cambium and scion cambium respond to being cut by forming masses of cells (callus tissues) that grow over the injured surfaces of the wounds. The union resulting from interlocking of the callus tissues is the basis of graftage. In dicots (e.g., most flowering trees) cambium—a layer of actively dividing cells between xylem (wood) and phloem (bast) tissues—is usually arranged in a continuous ring; in woody members new layers of tissue are produced annually. Monocot stems (e.g., lilacs, orchids) do not possess a continuous cambium layer or increase in thickness; grafting is seldom possible.

    The success or failure of any grafting operation is based upon the compatibility of each plant part, closeness of fit, and cambial contact. The union is initially held in place by pressure exerted by the stock, by grafting tape, or by rubber budding strips applied over the point of union. Warm temperatures (80–85 °F ) increase callus formation and improve “take” in grafting. Thus grafts using dormant material are often stored in a warm moist place to stimulate callus formation.

    Budding is effected by raising or removing a segment of bark from the stock and inserting a segment of the scion, containing a bud, into the wound thus made. In bud grafting involving fruit trees, the bark is lifted away from around an upright or inverted T-shaped incision, and the bud is then inserted under the bark and tied securely in place.

    grafting methodsSome methods of grafting: (1) simple splice graft, showing cut surfaces of stock and scion and the cut surfaces joined and bound; (2) tongued graft; (3) whip graft; (4) cleft graft; (5) side cleft graft.© Merriam-Webster Inc.

    Grafting of a larger scion, on the other hand, usually involves the use of the complete circumference of a plant as the scion. Certain types of grafts thus may necessitate sawing through the trunk and inserting the scion in vertical slits made between the bark and wood of the trunk’s bared core.

    The establishment of union between grafted components is effected through the formation of a loose growth of cells (callus) contributed by both elements. These cells fuse into a mass so continuous in compatible grafts that the precise location of the line of union is frequently impossible to determine, even microscopically. Just as in wound healing, union proceeds more rapidly if the wounded areas are protected against drying out; and, in most forms of grafting, rapid knitting is essential to maintenance of life in the scion.

    In grafting and budding, the rootstock can be grown from seed or propagated asexually. Within a year a small amount of scion material from one plant can produce hundreds of plants.

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