What is Plant Grafting?
Plant grafting is the process of joining two plants to grow as a single entity. In most cases, one plant provides the roots and lower portion, known as the rootstock, while the other provides the upper, flowering or fruiting parts, known as the scion. The goal is to create a hybrid plant that takes advantage of the best qualities of each component. For example, a rootstock may offer disease resistance and hardiness, while the scion offers diversifying fruit varieties on a single rootstock.
Why Graft?
- Disease Resistance: Grafting can make plants more resistant to soil-borne diseases by using disease-resistant rootstocks.
- Improved Growth: By combining a vigorous rootstock with a fruitful scion, gardeners can often produce plants that grow faster and produce higher yields.
- Adaptability: Grafting allows you to grow plants in regions where they may not naturally thrive by using a local, hardy rootstock.
- Variety in Small Spaces: With grafting, you can grow multiple types of fruits on a single tree, perfect for gardeners with limited space.
- Faster Maturity: Seedlings take time to reach maturity, while grafted plants often mature faster, providing fruit or flowers more quickly.
Types of Grafting
There are several methods of grafting, each with its own benefits and specific applications:
1. Cleft Grafting
See pages 5-8 for step by step process : Grafting Fruit Trees
See pages 85-88 for step by step process: Budding and Grafting
- How It Works: A slit is made in the rootstock, and the scion is shaped into a wedge to fit securely. This method is ideal for rejuvenating old or unproductive trees.
- Best For: Larger rootstocks, particularly for fruit trees. Plants that commonly benefit from cleft grafting include most fruit trees like apples, pears, peaches, cherries, as well as ornamental plants like camellia varieties, where the technique is often used to topwork existing trees to change varieties or add multiple varieties to a single plant; making it a popular choice for home gardeners to modify established trees in their orchard.
2. Whip and Tongue Grafting
See video for step by step process: How to perform whip grafting of walnuts - UCANR
- How It Works: Both rootstock and scion are cut at a slant, and each has a small “tongue” cut to interlock, providing a tight and secure fit.
- Best For: Young trees and branches of equal diameter. Examples include apples, peaches, cherries, pears as well as camellia varieties. Plants that commonly benefit from whip grafting include apple trees, pear trees, stone fruits like plums and cherries, grapes, pecan trees, walnut trees and various citrus varieties; essentially, most fruit trees with relatively similar bark thickness and growth habits are good candidates for whip grafting.
3. Budding (Bud Grafting)
See video for step by step process:
Budding, Grafting and Planting Walnut Trees - UCANR
- How It Works: Instead of a scion, a single bud is inserted into the rootstock, allowing for efficient grafting and growth.
- Best For: Plants that commonly benefit from bud grafting include most fruit trees like apples, cherries, peaches, plums, pears, citrus fruits, as well as ornamental trees like roses, Japanese maples (Acer palmatum), magnolia, laburnum, and many varieties of flowering shrubs, making it a popular method for propagating desirable cultivars with specific traits on a suitable rootstock
4. Approach Grafting
See pages 105-107 for examples of approach grafting: Budding and Grafting
- How It Works: Both plants are grown side-by-side and their stems are fused without removing the scion from its original plant. Once fused, the scion plant is cut off below the graft.
- Best For: Plants that are difficult to graft using other methods. Plants that commonly benefit from approach grafting include fruit trees like mango, tamarind, avocado, citrus, apple, and pear, as well as ornamental plants like roses, junipers, and bougainvillea; essentially, any plant where you want to combine the desirable traits of one variety with the root system of another, especially when the desired variety is difficult to root on its own and other methods of grafting have been tried unsuccessfully.
5. Side-Veneer Grafting
See pages 12-13 for examples of veneer grafting: Grafting Fruit Trees
- How It Works: The scion is attached to the side of the rootstock with a slanted cut, usually performed on young rootstock in nurseries
- Best For: Plants that typically do well with side veneer grafting include conifers like spruce (Picea), fir (Abies), and juniper, as well as other plants like rhododendrons, camellias, Japanese maples (Acer palmatum), and dogwoods (Cornus spp.).
Tools Needed for Grafting
- Sharp Grafting Knife: Essential for making precise cuts.
- Pruning Shears: For trimming the plants.
- Grafting Tape or Rubber Bands: To secure the graft.
- Rooting Hormone (optional): Can aid in graft success.
- Wax or Sealant: To protect the grafted area and prevent moisture loss.
Sourcing Healthy Rootstock and Scions
To source healthy rootstock and scions for grafting, look for young, vigorous trees with disease-free growth, ideally selecting one-year-old wood from the middle section of a branch, ensuring the rootstock is compatible with the desired scion variety and considering factors like desired tree size, pest resistance, and climate suitability when making your selection; always check for signs of disease or damage before taking cuttings.
Key points for choosing healthy rootstock and scions:
Scion selection
- Growth stage: Choose wood from the previous year's growth, typically pencil-thick shoots with healthy buds.
- Branch location: Select middle sections of branches, avoiding overly vigorous or weak growth.
- Disease check: Inspect for signs of disease or pest damage on the chosen branch. Never source scions from plants restricted to quarantined counties. If you have questions contact the local county agricultural department.
- Variety compatibility: Ensure the scion variety is compatible with the chosen rootstock.
- Resource: The California Rare Fruit Growers is an invaluable source for advice on scions, rootstock and grafting. Certain times of the year they have scion exchanges in local counties.
Rootstock selection
- Desired characteristics: Consider factors like tree size (dwarfing vs. standard), disease resistance, and climate adaptability when choosing a rootstock.
- Age: Opt for young, healthy rootstock trees with good root development.
- Source: Consider obtaining rootstock from a reputable nursery specializing in grafting materials. Source disease resistant varieties of rootstock if possible. Never source rootstock from plants restricted to quarantined counties. If you have questions contact the local county agricultural department.
Step-by-Step Guide to Cleft Grafting
Fruit Tree Grafting Mini Lesson
- Select Healthy Plants: Ensure both rootstock and scion are disease-free and healthy. Young healthy rootstock is better than older rootstock.
- Prepare the Rootstock: Make a clean cut across the top of the rootstock stem and split it down the middle.
- Prepare the Scion: Cut the scion into a wedge shape, ensuring it has at least two buds.
- Insert the Scion: Place the scion wedge into the split rootstock, ensuring cambium layers (the green layer just under the bark) align. This is important, unless the cambium in the scion and rootstock are aligned, the graft will not take.
- Secure the Graft: Use grafting tape or rubber bands to secure the graft tightly.
- Provide Proper Care: Keep the grafted plant moist and in a shaded area, checking regularly for signs of growth.
Tips for Successful Grafting
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Time It Right: Grafting is most successful in early spring or late winter when plants are beginning to emerge from dormancy.
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Choose Compatible Plants: Some plants graft better with related species. For example, apples and pears can be grafted onto each other but not onto unrelated trees.
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Keep the Graft Moist: Proper hydration and protection from extreme weather is crucial during the healing process.
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Practice Patience: Not all grafts take immediately; some may take weeks or even months to show signs of growth. Grafting is both a science and an art. Don't expect to get it right the first time, but with practice and carefully following the recommended techniques you will be successful.
Common Issues and How to Troubleshoot
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Failure to Connect: This often happens if the cambium layers weren't aligned. Ensure the cuts are clean and match well.
- Graft Rejection: If a graft is unsuccessful, it could be due to incompatibility. Research which rootstocks are most compatible with your scion species.
- Drying Out: Make sure the graft area is well-sealed and moist to prevent desiccation.
The Future of Grafting: Innovations and Trends
Modern grafting techniques and rootstock innovations have made grafting more accessible than ever. With advancements in hybrid rootstocks and precision grafting, gardeners are able to grow plants that resist diseases, withstand environmental stresses, and produce higher-quality fruit. New technology, such as robotic grafting in commercial settings, allows for even more precision and efficiency.
Final Thoughts
Grafting is both an art and a science that requires patience, skill, and a bit of experimentation. For gardeners, it's a way to take control over the traits of their plants, creating healthier, more productive specimens. Whether you're grafting to grow a stronger plant or to simply learn and enjoy the process, mastering this technique can add a valuable skill to your gardening repertoire. Give grafting a try, and you might find it to be one of the most rewarding parts of your gardening journey!
References:
Great source of information and scion/rootstock: California Rare Fruit Growers: https://crfg.org
Rich information of basic grafting techniques: https://ccag-eh.ucanr.edu/files/241489.pdf
Techniques in Grafting Fruit trees: https://ucanr.edu/sites/uccemerced/files/164695.pdf
Stone Fruit Budding and Grafting: https://ucanr.edu/sites/btfnp/fruitnutproduction/Stone_Fruit_Propagation/grafting/
Grafting Tomatoes: https://ucanr.edu/sites/mgslo/files/260518.pdf
Grafting and Budding from the California Backyard Orchard Website (UCANR): https://homeorchard.ucanr.edu/The_Big_Picture/Propagation/#grafting-budding
Grafting Dormant Deciduous Fruit Scions (CRFG): https://ccmg.ucanr.edu/files/172574.pdf
Budding and Grafting Demystified (UCANR): https://ucanr.edu/sites/mgscc2016/files/387157.pdf
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