Background: 

Apples (Malus domestica) are best known for their role as a cheap, convenient, and nutritious snack. The fruits are native to what is now Central Asia, its wild ancestor being Malus sieversii. (Encyclopedia Britannica) Apples later made their way to Europe and the Western Hemisphere via travelers and trade. The apple fruit itself contains a ripened ovary surrounded by crisp, fleshy, and sweet tissues. Apples are also a highly diverse fruit with over 2,500 varieties grown in the United States and 7,500 varieties grown around the globe. (University of Illinois at Urbana-Champaign) Depending on the type, apples come in all shapes, sizes, and colors. Apple trees are easy to grow and provide a bounty of fruit each year after they reach maturity.  

 

Grafting Background

Grafting is the practice of joining two or more plants together so that they can grow and act as one. The more closely related the plants are to each other, the more likely a graft union will be successful. In other words, the two plants being grafted together must have a relationship such as being in the same family or being the same species. Grafting is a useful method to produce plants that aren’t reproducible by other methods, produce specific clones, hasten reproductive maturity, repair damage, and develop seed trees of older, superior plants. There are many different methods of grafting, but this tutorial in deciduous apple tree grafting will focus specifically on the whip and tongue method.  

 

Materials:

• Healthy rootstock.  
• Healthy scion. 
• A sharp knife.
• Grafting tape. 
• Plastic wrap.  
• Gloves (to protect hands).  

 

Graft Information & Requirements

Some Terms to be Familiar With:  

Scion – a detached but living portion of a plant to be attached to a rootstock. 

Rootstock – underground and/or near above-ground part of the plant from which new growth can be formed.  

Cambium – location of cell division.  

• In grafting, the vascular cambiums of the scion and rootstock must make intimate, direct contact to allow for the wound to heal and for xylem and phloem to redevelop to transport nutrients and water from the roots to the top of the plant. 

Understock – location where the scion and rootstock make intimate contact.  

Requirements for a successful graft include:  

1. Scion and rootstock must be compatible.  
2. Close cambial proximity between scion and rootstock.  
3. Rootstock and scion must be in the proper physiological state.  
4. Cut surfaces must be protected from desiccation.  
5. Appropriate care and environmental conditions must be given for a period following the grafting procedure. 

 

Procedure

1) Collect scion wood to graft onto rootstock.  

• Collect scion wood early in the day when temperatures are cool.  
• The best type of scion wood to collect is from the current season’s growth or dormant wood that grew the previous year. (Penn State Extension) 
• To store, place the scion wood into airtight plastic bags, label them, and promptly put them in a refrigerator if they’re not going to be used immediately. Optimum temp to store scion wood at ranges from 32-45 degrees Fahrenheit. 

Before Grafting: 

High success rates are seen with whip & tongue grafts due to high amounts of surface contact between the cambial layers.  

Splice grafts are simple versions of whip & tongue grafts. While easier to do, splice grafts are not as ideal due to not being as stable as shown in the comparison image below:  

https://courses.cit.cornell.edu/hort494/mg/methods.alpha/WTMeth.html

• According to the North Carolina State Extension, the best way to make a whip and tongue graft is to “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.” 
• The graft process relies on “interlocking” between the scion and rootstock.  
• Make sure that the scion and rootstock are of similar diameter, so they fit together.

2) Cut the scion.  

NOTICE: It is very easy to cut yourself during the cutting process. Wear gloves to protect hands and fingers during steps 2 and 3. 

• You should use a scion section that contains 2-3 buds.  
• Identical cuts are made at the top of the rootstock and the bottom of the scion, so they can fit together to form the graft union. 
• The first cut is about 1-2.5 inches long and made at an angle with one long and continuous motion of the knife. This first cut should be made on the scion in the internode area below the two or three buds. (North Dakota State University) 
• Cut should be made in the proximal end of the scion (end that was closest to the original rootstock) as shown in the diagram below: 

http://irrecenvhort.ifas.ufl.edu/plant-prop-glossary/06-grafting/02-graftingtypes/10-grafting-root.html

• Smooth cuts are essential so that good cambium layer contact will occur. 

https://courses.cit.cornell.edu/hort494/mg/methods.alpha/WTMeth.html

3) Cut the rootstock.  

• On the rootstock, an identical cut is then made.  
• A second cut is started about 1/3 of the way down from the tip of the first cut. This second cut should be about half as long as the first cut and made parallel to the first. (North Dakota State University) 
• Once the second cut is made, the rootstock and scion should interlock as show below:  

https://courses.cit.cornell.edu/hort494/mg/methods.alpha/WTMeth.html

4) Making the graft union.  

• Interlock the scion and rootstock. Make sure the cambial layers make intimate contact.  
• Holding both the scion and rootstock in place, wrap with parafilm and grafting tape to keep the union together for healing and to seal in moisture. 

 

After Care

• After the grafting process is complete, the tree(s) should be moved to a warm area with high humidity to allow the area of the union to heal.  
• During the healing process, the scion and rootstock will grow onto each other as new xylem and phloem are formed to allow water and nutrients to be transported from the roots up into the new scion.  

NOTICE: Not all graft unions are successful. Failure of the graft union can result in any of the following symptoms of incompatibility:  

1. Yellowing of foliage or defoliation.  
2. Premature death.  
3. Differences in growth rate between the scion and rootstock.  
4. Overgrowth.  
5. Suckering.  
6. Graft breaks completely.  
7. Plant just dies.  

 

Works Cited:

Aasheim, M. (n.d.). Propagation of Apple Trees. Retrieved October 31, 2019, from https://www.ndsu.edu/pubweb/chiwonlee/plsc368/student/papers02/maasheim/appleprop.htm. 

Apple Facts. (2019). Retrieved October 31, 2019, from https://web.extension.illinois.edu/apples/facts.cfm. 

Crassweller, R. (2019, October 16). Fruit Tree Propagation – Grafting and Budding. Retrieved October 31, 2019, from https://extension.psu.edu/fruit-tree-propagation-grafting-and-budding. 

The Editors of Encyclopedia Britannica. (2019, February 4). Apple. Retrieved October 31, 2019, from https://www.britannica.com/plant/apple-fruit-and-tree. 

Weinmann, T. (n.d.). Grafting and Budding Fruit Trees. Retrieved October 31, 2019, from https://www.ag.ndsu.edu/hort/info/fruit/graft.htm. 

Whip & Tongue Grafting. (n.d.). Retrieved October 31, 2019, from https://courses.cit.cornell.edu/hort494/mg/methods.alpha/WTMeth.html.