Whip Grafting

Grafting is one of the oldest methods of plant propagation and is standard practice today for various types of fruit trees. Whip grafting is an easy technique for the beginner, and has yielded good results for me with apples, apricots, plums and cherries. There are several other grafting techniques - bud grafting, cleft grafting, and bark grafting being some of the common ones.

Why is grafting important for the home orchardist?

• This is a useful technique for people with small backyards. Instead of a tree bearing a large quantity of the same variety of fruit at once, you can spread the harvesting season (since different varieties ripen at different times) and harvest multiple varieties of fruits, with different flavors, shapes and sizes. Over a few years, I have been able to graft nine to twelve varieties on each of my apple, plum, peach and apricot trees.

• Some fruit trees cannot reliably be grown from seeds, because the seeds do not retain the characteristics of the parent plant. Grafting allows us to grow the identical fruit.

• By using the appropriate “rootstock,” one can control the size and growth of the tree, and also select rootstock that’s suitable for the given soil conditions. For example, the San Francisco Bay Area has a lot of clay soil, which does not allow for easy drainage of water, and can cause diseases in fruit trees. There are various varieties of rootstock that tolerate such soil conditions.

• Certain varieties of fruits require pollinizers, and, instead of planting multiple fruit trees, one can simply graft a variety of pollinizer on the fruit tree to be pollinated, thus eliminating the space and care needed for an entire fruit tree.

Not every fruit is easy or possible to graft. For example, figs have challenges with grafting, because of the sap they release. Some folks have come up with novel solutions to graft figs, but I haven’t tried them yet. I propagate figs by rooting them… would love to write an instructable on that process sometime.

Sources of Scions:
a) If one of your friends or relatives is growing a fruit you like, you can take a cutting and graft it
b) If you establish rapport with the manager of the local nursery, he/she may let you take some cuttings
c) If there is a local orchard or farm in the area, you can find out when they prune their trees, and they’ll likely let you take cuttings
d) Residents of some western states can become members of the local chapter of the CRFG (California Rare Fruit Growers - Link) and participate in the annual scion exchange, where you can get access to hundreds of varieties of fruit.
e) The USDA (U.S. Department of Agriculture) maintains a live “Germplasm Bank” of thousands of fruit varieties (Link), and you can contact the local resource for scions.

When to do whip grafting? I graft varieties when the trees are just coming out of dormancy, from mid February to mid March, in the San Francisco Bay Area.

Compatibility
We need to observe compatibility between the scion and the host branch. For example, while there is high compatibility between stone fruit (peaches, apricots, plums and nectarines), you can’t graft a peach on an apple. Similarly, there is strong compatibility between apples and pears but you can’t graft apples on oranges and vice versa.

Different varieties of citrus (limes, lemons, mandarins, oranges, etc.) are highly compatible with each other, but different grafting techniques are followed for them, such as bud grafting, since citrus isn’t deciduous i.e. does not go dormant as the stone fruit do.

In January I collect the varieties I want to graft on to my fruit trees. I cut the branches to fit a plastic sealable bag, and put a damp piece of napkin in the bag to keep them from drying out. I label each bag with the name of the variety and type of fruit, and place the bag in the fridge (not the freezer).

If the scion dries out before the graft is established, the branch will die, so we need to do our best to keep the branch from drying out. Before the scion is grafted, we keep it "wet" by placing a damp napkin in the bag, and, after the scion is grafted, we keep it from drying out by covering it with latex paint or grafting tape.

The images are from the 2014 CRFG-SCV (California Rare Fruit Growers, Santa Clara Valley Chapter) Scion Exchange. Hundreds to thousands of varieties of scions are available at such exchanges!

When it’s time to graft (mid February to mid March), I match the diameters of the scion and the host branch. I can match the diameters of the sips using a vernier caliper, or just visually. Matching the diameters has been yielding good results.

Why is it important for the diameter to match? The nutrients are carried with the "cambium layer," placed just below the bark. The better the contact between the cambium layer of the scion and the host branch, the better the likelihood that the graft will succeed.

I use a sharp blade to cut the host branch to prepare it to join the scion.

This figure shows the host branch and the scion wood that would be grafted on the host. The two are of approximately the same diameter. This is one last step to check the diameter, to make sure the host and scion are approximately of the same diameter.

In some other grafting styles, it is less important for the diameters to match, because of the way the scion and host branch are put in contact.

I use a sharp blade to cut the host branch at an angle, and I will cut the scion at a matching angle so that the two would join. While some people like to use specialized grafting knives, these commercial knives work well for me; I don’t have to sharpen the blades, and I can easily buy new blades for them. I like to make a single cut, to keep it straight, and a longer cut provides greater surface area for the joint, improving the likelihood of a good contact between the host branch and the scion.

I cut the scion at a matching angle so that it would join the host branch. Sometimes it takes a few cuts to get to a good march. The goal here is to connect the cambium layers of the two pieces of wood, so that nutrients would flow from the host to the scion.

In the entire process described here, cutting the host branch and the scion properly (for a good joint), is what takes more practice.

A modification of the whip graft of the "whip and tongue" graft, which I plan to describe in a different Instructable.

When placed together, the host branch and scion should match. The goal here is to connect the cambium layers of the two pieces of wood, so that nutrients would flow from the host to the scion.

Once I have achieved a good fit, two more objectives remain:
a) Providing mechanical stability between the host branch and the scion: I tie the two branches with a piece of rubber band or electrical tape.

b) Keeping the scion from drying off. I apply paint over the joint and the entire length of the scion, to prevent the scion wood from drying off. Household latex paint works well. Some folks use grafting tape, parafilm tape, or plastic tape to cover the scion.

I put a label near the graft to identify the variety and the date, and I record on a spreadsheet when I grafted what variety on which tree.

The attached spreadsheet shows the various varieties I have been able to graft on my fruit trees over the years, and the image shows how I'm able to harvest fruit year-round by having a wide variety of fruits, and extending the growing season of each type of fruit.

I did a lot of grafting on this apricot tree and it bears eight varieties of apricots. The images show the growth in a few weeks to a few months.

If you look in the center lower third of the picture you can still see the graft union. It's amazing how much growth has taken place in just three months.

I did a lot of grafting on this apple tree and it bears twelve varieties of apples. Between two dwarf apple trees, I'm able to get about twenty varieties of delicious apples.

If the scion is from last year's growth, it will likely have buds, which will form flowers in the coming spring, so you can get fruit a few month after you graft the new variety. If the scion is from older growth, it will likely not have buds, so you'll likely have to wait another year for the scion to grow branches and bear fruit.

Grafting has allowed me to do various interesting things, for example, I was able to "define" trees with:
- a white peach and a yellow peach, and a white nectarine and a yellow nectarine, one the same tree
- the top half of a peach tree growing one variety, and the bottom half growing another
- many varieties of plums growing on the same branch
- so many varieties on apple trees that each branch is a different variety

The different varieties of fruit lead to different shapes / colors / sizes / ripening times for each branch, and this looks really neat!

To have a high success rate, you need to get the following right:
a) For deciduous trees, time the grafting process so that the grafts are in place before new growth appears in spring
b) Make sure the host and scion are compatible
c) There must be good contact between the host and scion, so that the cambium layer can transport nutrients to the new branch
d) There should be good pressure at the joint, for mechanical support and for maintaining good contact between the cambium layers
e) The scion must not dry out before or after the graft
f) You should cut branches immediately below the graft so that the nutrients are pushed into the grafted branch instead of getting divided among various branches