Altoire grafting

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1. Grafting and Budding Nursery Crop Plants AG-396 GraftingWhen to Graft Unlike budding, which can be performed before or during the growing season,most grafting is done…
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  • 1. Grafting and Budding Nursery Crop Plants AG-396 GraftingWhen 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 rootstockare still dormant. Containerized plants may be moved indoors during the actualgrafting process; after grafting, these plants are placed in protected areas or inunheated overwintering houses. Field-grown stock, of course, must be grafted inplace. Some deciduous trees are commonly grafted as bare rootstock during thewinter and stored until spring planting. Indoor winter grafting is often referred to asbench 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
  • 2. season. Scions should be severed with sharp, clean shears or knives and placedimmediately in moistened burlap or plastic bags. It is good practice during theharvesting 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 quitereadily. An alternative sterilizing solution may be prepared by mixing one parthousehold bleach with nine parts water (by volume). However, this bleach solutioncan be highly corrosive to certain metals. For best results, harvest only as much scion wood as can be used for graftingduring 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 inlower 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 32o to 34oF. 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 budmust be aligned with the vascular cambium of rootstock. In woody plants thecambium 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 additionto stimulating tissue growth on the basal ends of many vegetative cuttings beforethey have rooted.
  • 3. Figure 1. Cross section of a woody plant stem.Types of Grafts Nurserymen can choose from a number of different types of grafts. This sectiondescribes 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 topropagate varieties of camellias that are difficult to root. This type of grafting isusually done during the winter and early spring while both scion and rootstock arestill dormant. Cleft grafting may be performed on main stems or on lateral orscaffold branches. The rootstock used for cleft grafting should range from 1 to 4 inches in diameterand 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 and8 inches long are usually the easiest to use.
  • 4. Figure 2. Cleft graft. Preparing the Rootstock. The stock should be sawed off with a clean, smoothcut perpendicular to the main axis of the stem to be grafted. Using a clefting toolwedge and a mallet, make a split or "cleft" through the center of the stock anddown 2 to 3 inches. Remove the clefting tool wedge and drive the pick end of thetool into the center of the newly made cleft so that the stock can be held open whileinserting the scion. Preparing the Scion. In cleft grafting, one scion is usually inserted at each endof the cleft, so prepare two scions for each graft. Select scions that have three orfour good buds. Using a sharp, clean grafting knife, start near the base of the lowestbud and make two opposing smooth-tapered cuts 1 to 2 inches long toward thebasal end of the scion. Cut the side with the lowest bud slightly thicker than theopposite side. Be sure the basal end of the scion gradually tapers off along bothsides. Inserting the Scion. Insert a scion on each end of the cleft, with the wider side ofthe wedge facing outward. The cambium of each scion should contact the cambiumof the rootstock. Securing the Graft. Remove the clefting tool from the cleft so that the rootstockcan close. Pressure from the rootstock will hold the scions in place. Thoroughlyseal all cut surfaces with grafting wax or grafting paint to keep out water andprevent drying. If both scions in the cleft "take," one will usually grow morerapidly than the other. After the first growing season, choose the stronger scion andprune out the weaker.
  • 5. NOTE: The temperature of grafting wax is critical. It must be hot enough to flowbut not so hot as to kill plant tissue. Recently, paint-like sealants have replaced waxin 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 fruitingtrees. In contrast to cleft grafting, this technique can be applied to rootstock oflarger diameter (4 to 12 inches) and is done during early spring when the bark slipseasily from the wood but before major sap flow. The rootstock is severed with asharp saw, leaving a clean cut as with cleft grafting. Figure 3. Bark graft. Preparing the Stock. Start at the cut surface of the rootstock and make a verticalslit through the bark where each scion can be inserted (2 inches long and spaced 1inch apart). Preparing the Scion. Since multiple scions are usually inserted around the cutsurface of the rootstock, prepare several scions for each graft. Cut the base of eachscion to a 1 ½- to 2-inch tapered wedge on one side only. Inserting the Scion. Loosen the bark slightly and insert the scion so that thewedge-shaped tapered surface of the scion is against the exposed wood under the
  • 6. flap of bark. Push the scion firmly down into place behind the flap of bark, replacethe bark flap, and nail the scion in place by driving one or two wire brads throughthe bark and scion into the rootstock. Insert a scion every 3 to 4 inches around thecut perimeter of the rootstock. Securing the Graft. Seal all exposed surfaces with grafting wax or graftingpaint. Once the scions have begun to grow, leave only the most vigorous one oneach stub; prune out all the others. Bark grafts tend to form weak unions andtherefore 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 graftingvarieties of camellias and rhododendrons that are difficult to root. Currently, it isthe most popular way to graft conifers, especially those having a compact or dwarfform. Side-veneer grafting is usually done on potted rootstock. Figure 4. Side veneer graft 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. Afterexposure to cold weather for at least six weeks, the rootstock is brought into a coolgreenhouse for a few days before grafting takes place to encourage renewed rootgrowth. 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 thestem on the potted rootstock to expose a flap of bark with some wood still attached.
  • 7. Make an inward cut at the base so that the flap of bark and wood can be removedfrom the rootstock. Preparing the Scion. Choose a scion with a diameter the same as or slightlysmaller than the rootstock. Make a sloping cut 3/4 to 1 inch long at the base of thescion. (Use the bark grafting technique shown in Figure 3.) Inserting the Scion. Insert the cut surface of the scion against the cut surface ofthe rootstock. Be certain that the cambia contact each other. Securing the Graft. Hold the scion in place using a rubber grafting strip, tape, orgrafting 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 thebinding material to girdle the stem.Splice Graft Splice grafting (Figure 5) is used to join a scion onto the stem of a rootstock oronto an intact rootpiece. This simple method is usually applied to herbaceousmaterials that callus or "knit" easily, or it is used on plants with a stem diameter of1/2 inch or less. In splice grafting, both the stock and scion must be of the samediameter. Figure 5. Splice graft. Preparing the Stock and Scion.Cut off the rootstock using a diagonal cut 3/4 to1 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 arubber grafting strip or twine. Securing the Graft. Seal the junction with grafting wax or grafting paint. Waterrootstock sparingly until the graft knits. Over watering may cause sap to "drown"
  • 8. 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 graftnursery crops or woody ornamentals. Both the rootstock and scion should be ofequal size and preferably no more than 1/2 inch in diameter. The technique issimilar to splice grafting except that the whip on the rootstock holds the tongue ofthe 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 asmooth 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. Figure 6. Whip and tongue graft. Preparing the Stock and Scion. Cut off the stock using a diagonal cut. The cutshould 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, halfwaybetween the bark and pith (on the upper part of the cut surface). Use a single knifestroke to draw the blade down at an angle through the wood and pith. Stop at thebase of the initial diagonal cut. This second cut must not follow the grain of thewood but should run parallel to the first cut. Inserting the Scion. Prepare the scion in the same way. Fit the scion into the
  • 9. rootstock so that they interlock whip and tongue. Be certain that the cambia arealigned. Securing the Graft. Wrap the junction with a grafting strip or twine, and seal itwith grafting wax or grafting paint. Never allow the binding material to girdle thestem.Saddle Graft Saddle grafting (Figure 7) is a relatively easy technique to learn and oncemastered can be performed quite rapidly. The stock may be either field-grown orpotted. Both rootstock and scion should be the same diameter. For best results, usesaddle grafting on dormant stock in mid- to late winter. Stock should not be morethan 1 inch in diameter. Figure 7. Saddle graft. 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 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 sameslope so that a maximum amount of cambial tissue will make contact when the twohalves 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; otherwiseadjust as needed. Securing the Graft. Wrap the graft with a grafting twine, tape, or strip, then sealit with grafting wax or grafting paint.
  • 10. All of the preceding techniques are used to top work horticultural crops for aparticular purpose. Occasionally, however, grafting is used to repair injured ordiseased plants. Two common techniques available for this purpose are bridgegrafting and inarch grafting.Bridge Graft Bridge grafting (Figure 8) is used to "bridge" a diseased or damaged area of aplant, usually at or near the base of the trunk. Such damage commonly results fromcontact with grading or lawn maintenance equipment, or it may be caused byrodents, cold temperatures, or disease organisms. The bridge graft provides supportas well as a pipeline that allows water and nutrients to move across the damagedarea. Bridge grafts are usually done in early spring just before active plant growthbegins. They may be performed any time the bark on the injured plant "slips." Figure 8. Bridge graft. Preparing the Scion. Select scions that are straight and about twice as long asthe damaged area to be bridged. Make a 1 1/2- to 2-inch-long tapered cut on thesame plane at each end of the scion. Preparing the Stock. Remove any damaged tissue so the graft is on healthystems. Cut a flap in the bark on the rootstock the same width as the scion and belowthe injury to be repaired. Gently fold the flap away from the stock, being carefulnot to tear the bark flap. Inserting the Scion. First, insert and secure the scion below the injury; push thescion under the flap with the cut portion of the scion against the wood of theinjured stem or trunk. Then go back and insert and secure the scion above theinjury following these same steps. Push the scion firmly into place. Pull the flapover 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 sothat they bow outward slightly. Bridge grafts should be spaced about 3 to 4 inchesapart across the damaged area.
  • 11. Securing the Graft. Secure all graft areas with warm grafting wax or graftingpaint. During and after the healing period, remove any buds or shoots that developon the scions.Inarch Graft Inarching, like bridge grafting, is used to bypass or support a damaged orweakened area of a plant stem (Figure 9). Unlike bridge grafting, the scion can bean existing shoot, sucker, or watersprout that is already growing below andextending above the injury. The scion may also be a shoot of the same species asthe injured plant growing on its own root system next to the main trunk of thedamaged tree. With the inarching technique, the tip of the scion is grafted in abovethe injury using the same method as for bark or bridge grafting. Figure 9. Inarch graft.
  • 12. Grafting, Pruning and CompostingPosted on May 1, 2011 by barbaramatthews Friday afternoon our class had a hands-on workshop. We split off into three groups, and visited grafting, pruning, andcompost stations. I had previously done some pruning and composting (although I didn’t really know the technicalities ofeither), but had zero experience with grafting. My first stop was the grafting station. I learned that grafting is the fusing of one plant’s tissues with another. One plant ischosen for its roots, and is referred to as the root stock, while the
  • 13. other is selected for its stems, leaves, flowers, or fruits–it is refered to as the scion. *It can take 5 t0 15 years (depending on thespecies) for a tree to mature and produce fruits, but a scion fused with a mature root stock will fruit in as little as two years; thisis one of the greatest benefits of grafting. We practiced grafting with the stem of a pear tree; we cut the stem (scion) in half and pretended that one part was a rootstock. The key to successful grafting is notching the root stem, and slicing the scion in such a way that they fit together like apuzzle piece–theirvascular cambium tissues in full contact with one another. (This is the green edge found upon cuttinginto the wood). The point at which the scion and root stock are connected is then wrapped in special grafting tape; this will holdthem togethe r until the tissues have merged. My group’s second stop was the pruning station, where we worked on a pear tree. We learned that the main reason forpruning is to increase fruit yield and ensure the health of the tree. To do this, examine the strongest of the branches in themiddle of the tree, and choose one to be thecentral leader; this branch’s orientation will determine which other branches andstems are pruned. *The central leader should receive as much direct sunlight as possible. Any branch or stem which is shadingor crossing the central leader should be removed. *Keeping the tree pruned will concentrate nutrients, ensuring quality fruits. Our last stop was the composting station. We learned that compost is made up of four elements: nitrogen, carbon, water, andair. For nitrogen, add layers of green plants and manure; for carbon add layers of brown/woody materials–such as leaves, strawand mulch. Keep adding layers–each hosed down with water–until you have a pile of compost that is at least 3×3 foot. Leavethe pile sitting for four days and then flip it, so that the bottom layer becomes the top. *Do this to ensure the compost staysaerated. Also flip on days 7, 11, and 18. After day 18, the compost will be ready for use as a fertilizer and soil amendment. I had a great time doing this workshop; especially the grafting aspect. I prefer fresh air and sunshine to a classroom anyday. Also, I find that working hands-on with a subject helps me to better understand and absorb the information beingpresented; it’s an excellent approach to education.
  • 14. Otherwise known as top working or grafting over, this is a technique forconverting an apple tree which is growing OK in the right place but whose fruit isunacceptable for some reason and you want to replace it with a different variety.This is much better than digging out the tree and replacing it with a new one andis used commercially. As mentioned elsewhere, I have done this a few times over
  • 15. the past few years, once when I realised that Spartan was very prone to scab andalso did not sell well-I grafted over 40 trees to Suntan and Ashmeads Kernel (Ihave not regretted this one bit) and in the spring of 2007 when I grafted over 8cider apple Crimson King (not to be confused with the 70s prog rock band KingCrimson) to 4 each of Harry Masters Jersey and Dabinett, as the latter 2 varietiesproved to be far better on our land. So far these are growing OK and the picturesin this page are taken from this example. The picture immediately below shows atree after top working, in April. Note that it has been cut back severely and severalpolythene ties can be seen, see below for close ups and explanations.Top working can employ more than one grafting style. In this case, I used saddlegrafts, cleft grafts, rind grafts and stab grafts. Like many things in life, if you get anunderstanding for the basic techniques and unde
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