As the seasons change, we are entering the time of year for grafting fruit trees. The best time of year for most types of grafting is in the dormant season, or in the winter when the plant is not actively growing. However, bud grafting (the focus of this article) is usually done in the late summer. For late summer grafting, check that the bark is “slipping,” or is easily peeled back from the tree rather than breaking or tearing to determine that it is a good time to attempt a bud graft.
In general, grafting is a technique used to propagate specific fruit varieties by inserting a piece of a desired plant into the rootstock or branch of another plant, which if successful grows out to be a new plant or branch of the transferred variety. All named varieties of fruit (‘Goldrush’ apple, ‘Santa Rosa’ plum, etc) are propagated through vegetative (asexual) reproduction rather than through seed; for the common pome and stone fruits, this is almost always done through grafting.
In addition to producing new trees of selected varieties, grafting can also be used to grow more than one variety or even different kinds of fruit on one tree. To determine with types of trees can be grafted together, it is best to remember that only closely related plants are compatible. For example, one can easily graft one variety of apple onto another type of apple tree. However, it is also possible to combine different fruits of the same genus. Many stone fruits are compatible with each other; a ‘fruit salad tree’ combines plums, apricots, and peaches all on the same plant! Some plants are even compatible with closely related species outside the genus; pears are sometimes grafted onto quince rootstocks, for example.
At the bottom of this article, there is a chart that details some common fruit tree compatibility: Rootstock Compatibility Chart
There are many different types of grafting (see links at end of article for more info), including:
Cleft grafting is a common technique used to change the variety of a tree or add a new variety onto an existing tree. It is accomplished in late winter and involves inserting the desired plant branches into a cleft made in a limb or rootstock of another plant.
Whip and tongue grafting is completed in late winter and fuses a branch from one desired variety onto a rootstock or existing branch of the same diameter. Most commonly done as a ‘bench graft’ completed indoors rather than in the field.
Bridge grafting is a technique used to repair damaged trees. It is performed by inserting new branches into the injured part of the tree and then letting the tree heal around them.
Bud grafting is a relatively easy technique that transplants a leaf bud from one tree to another. Although it may seem like an intimidating and technical process, it is really quite simple and requires only a few common tools. The rest of this article goes into the specifics of bud grafting and its benefits.
Steps for Bud Grafting:
- Gather a sharp pocket knife and some grafting tape. This specific kind of tape stretches as the plant grows and is fungus-resistant. If you don’t have any, you can buy it here, or just use a thick plastic bag cut into strips.
- Select a vegetative bud (leaf bud) located about halfway down a branch on the selected tree. Fruiting buds tend to be rounder and stick out from the stem, as opposed to vegetative buds which tend to be pointier and pressed against the stem. See the picture below for comparisons between a leaf/vegetative bud and a fruiting bud.
3. Cut out a ½ inch shield shape around the bud, being careful to only cut into the bark and not the pith. The pith is the colored, fleshy part of the branch that runs right through the center. Remove any existing leaf from the removed bud but keep the leaf stalk (petiole).
4. On the branch you will be grafting onto, remove all leaf buds or side branches
5. Make a 1 inch, T-shaped cut on the bark of the branch
6. Peel back the bark and insert the new bud into the branch. Make sure the bud is oriented the same way on the new branch as it was on the old (generally, pointing up)!
7. Wrap the area around the bud with grafting tape
If the bud takes, the bark and cambium layer of the host tree will heal around the new bud. If the bud withers and dies, it means that the graft did not take. This will usually happen within a month. Just before the next growing season (early spring), locate all places where bud grafts have successfully taken. Then, clip off the rootstock branch right above where the grafted bud was placed, as this will redirect the energy into the bud and allow it to grow quickly.
Bud grafting is often a preferred method of grafting as it has a high success rate of the buds taking. Bud grafting can fail if the knife is not sharp enough, the cuts are not precise, or any number of other reasons. Mostly, however, it is a good technique for beginners because it requires only a single bud to be moved, rather than a piece of the plant. It is also possible to graft multiple buds to a plant in the hope that some will take.
To give your grafts the best chance of taking, it is important to use a good, well-sharpened knife. A dull knife will tear the edges around your cuts rather than providing clean slices. In a good grafting knife, it is helpful if the knife is small and slightly curved to assist your cuts. Many grafting knives are only sharp on one side, so be sure to watch for that if you are left-handed. Some recommended knife varieties are the Felco Victorinox and the Opinel. For sharpening your knife, a good, multi-purpose sharpener is the Pocket Pal Multifunction Sharpener.
If you are interested in being creative with your fruit trees and experimenting with different varieties, bud grafting is a good way to get introduced to the grafting techniques. The exact time of year when it is ideal to graft varies with the specific grafts you are doing as well as the temperature, so it is best to look up your specific locations and plants before beginning to graft. Overall, this is a fun way to learn more about your plants, as well as create some new ones!
Find more details and instructions on the different types of grafts here.
References and more info:
This POP Blog Post prepared by 2019-20 POP Intern Bethany Bronkema with assistance from POP staff Alyssa Schimmel and Phil Forsyth.
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