Grafting Fruit Trees Step-by-Step

This step-by-step guide to grafting fruit trees shows how to graft a tree using a very useful technique called the Z-graft.

This step-by-step guide shows how to graft fruit trees such as citrus trees with the Z-graft.
This step-by-step guide shows how to graft fruit trees such as citrus trees with the Z-graft.

Z-grafting is a scion grafting technique that is very helpful for grafting trees in situations where the scion and rootstock have different diameters. I have found the Z-graft especially useful for grafting citrus trees when the scion diameter is greater than that of the rootstock. It is useful both for grafting new trees and also to add new varieties to established trees.


Grafting Fruit Trees Step-by-Step by Z Grafting  – YouTube Video

In addition to this step-by-step grafting guide, I have also made a YouTube video (see below) showing how to graft fruit trees with the Z-graft.

Citrus Budwood from a Disease-free Source

Citrus cuttings have the potential to spread tree-killing diseases. It is often not apparent when a tree is infected with a fatal disease. This makes the source of citrus budwood for grafting very important.

In California where I live, we now have both exotic diseases that kill citrus trees and also the insects that spread the diseases. The situation is so severe that it now against the law in California to graft with cuttings taken from backyard citrus trees. To save our trees from deadly diseases, hobbyists in California no longer swap citrus cuttings with friends. We now instead order our budwood at a nominal cost from the Citrus Clonal Protection Program (CCPP), a program that exists to provide disease-free budwood for the grafting of citrus trees.

The CCPP will ship budwood anywhere in the world where the local government allows it. Many citrus growing regions where CCPP budwood is not allowed have their own disease-free citrus budwood programs. Here I have created a web page that lists some other programs: Citrus Budwood Programs.

The below YouTube video goes through in detail the process of setting up an account and placing a budwood order with CCPP.

Disinfecting Grafting Tools

disinfecting grafting tools
Disinfecting grafting tools.

In order to both maximize the probability that the graft lives and also to prevent the spread of disease from tree to tree, it is important to disinfect grafting tools between grafts. To learn more about disinfecting grafting tools, please see the following link: Disinfecting Grafting Tools.

 

 

 

Grafting the Valentine Pummelo Hybrid

The fruit grafted in this article is the Valentine pummelo hybrid, a delicious fruit created by the citrus breeders at the University of California, Riverside by crossing the Siamese Sweet Pummelo with a hybrid of a mandarin orange and a blood orange.

Rootstock Suckers

I had neglected this Cara Cara pigmented navel orange tree after I realized that the previous owners of my house had already planted a Cara Cara tree. Normally I would prune off roostock suckers like these, but since I already had a Cara Cara tree I decided to graft to the roostock suckers to convert this tree into a Valentine Pummelo tree.

Rootstock suckers.
Rootstock suckers.

Grafting a Large Diameter Scion to a Smaller Diameter Rootstock

Since the diameters of the rootstock suckers were smaller than the diameters of my Valentine Pummelo scions, I decided to graft my tree with the Z-graft. When scion grafting fruit trees I usually prefer a cleft graft or a bark graft, but when the diameter of the budwood that I receive from CCPP is larger than the branch to which I would like to graft, the Z-graft is a good choice.

Z-graft
The Z-graft.

Cutting the Top off of the Rootstock

The first step is cut off the top of the rootstock sucker at about a 45 degree angle.

Cutting the rootstock
Cutting the rootstock.

Cutting a Strip in the Rootstock

The next step is to cut off a small piece of the longer end of the rootstock at a very slight angle. Then I cut a thin strip in the longer end of the rootstock and leave it attached.

Cutting a strip in the roostock
Cutting a strip in the roostock.

Cutting the Scion

Next I cut off the bottom of the scion at about a 45 degree angle and cut off a small piece of the longer end. Sometimes scions have an angular shape such as this one does. With some tree grafting techniques this can cause a problem. With the Z-grafting technique I will use the angular shape to my advantage by cutting a thin strip from an angled part of the scion in the next step.

Cutting the scion
Cutting the scion.

I then cut a strip in the longer end of the scion. In order to make cambium contact with the rootstock, it is important that the width of this strip be less than the diameter of the rootstock.

Cutting a strip in the scion
Cutting a strip in the scion.

Fitting the Scion and Rootstock Together

Next I fit the scion into the rootstock to form the Z.

Inserting the scion into the rootstock.
Inserting the scion into the rootstock.

Cambium Contact

The cambium of a tree is a thin layer of plant tissue between the bark and the wood. The goal with all grafting techniques is to connect the cambium of the scion to the cambium of the rootstock. Grafting fruit trees with the Z-graft creates many points of contact between the cambium layers of the rootstock and scion. This makes for a successful graft and a strong graft union.

cambium contact
Points of cambium contact are shown by the blue arrows. Two different views of the graft are shown.

Wrapping with Parafilm-M

I wrap the graft union with a product called parafilm-M to seal the graft and hold it in place. For cleft grafting and bark grafting I use a different type of parafilm, but I find that parafilm-M is easier to stretch. I felt it would be easier to keep the cambium layers lined up while wrapping if I used parafilm-M. The disadvantage of parafilm-M is that I had to cut it ahead of time to make strips of the appropriate width. To get a good seal, I gently pull on the parafilm as I wrap it. This makes it stick to itself.

Wrapping the graft with parafilm-M
Wrapping the graft with parafilm-M.

Wrapping with a Rubber Band

In order to ensure close contact between the cambium layers and to strengthen the graft while it is healing, I wrap the graft with a rubber band.

Wrapping the graft with a rubber band
Wrapping the graft with a rubber band.

Wrapping with a Second Layer of Parafilm

Next I prune the scion to leave three or four buds and wrap the graft with a second layer of parafilm-M. I wrap starting from the bottom, overlapping as I go up. Overlapping the layers keeps the graft from drying out and will also keep out rainwater. Other than the buds, I completely wrap the scion, including the cut end.

Wrapping the graft with a second layer of parafilm-M
Wrapping the graft with a second layer of parafilm-M.

Grafting a Backup Scion

Since there were two rootstock suckers, I grafted two scions so that I would succeed even if one of the grafts failed. The graft that I showed above was my second graft (the backup). I am glad that I grafted the backup scion because I made a mistake on my first graft that is shown below. My mistake was to cut the scion such that the width of the scion was greater than the diameter of the rootstock. Because of this, the cambium layers did not touch on the top part of the Z.

First graft
First graft.

Citrus Z-graft Growing

I moved the tree to a shady area for three weeks for the graft to heal. The second graft began to grow four weeks after I moved the tree back into the sun.

Citrus graft growing.
Citrus graft growing.

Pruning off the Original Variety

After the second graft put on a bit of growth I cut off the original variety.

pruning off the original variety
Pruning off the original variety.

Picking the Winning Graft

The below photo shows the consequences of failing to connect the cambium layers at the top of the Z of the first graft. The graft was slow to grow because the cambium layers were only connected on the bottom. I pruned it off because the other graft did much better.

removing the partially healed first graft
Removing the partially healed first graft.

Healing of the Winning Graft

The winning graft healed well on the top and the bottom of the Z.

Healed graft.
Healed graft.

Staking the Tree

Next I staked the tree.

Staking the tree
Staking the tree.

Removing a Rootstock Sprout

By the following spring the tree had put on more growth including a sprout from the rootstock. Rootstock sprouts must be removed before they take over and crowd out the grafted variety.

Removing the rootstock sprout
Removing the rootstock sprout.

Finished Valentine Pummelo Tree

finished valentine pummelo tree
Finished Valentine pummelo tree.

Here is the finished tree ready to plant after a few more months.

Save Trees by Sharing

Please share this article with anyone that you think may be interested in grafting fruit trees. Knowledge of the importance of using a registered disease-free budwood source when grafting citrus will help to prevent the accidental spread of deadly citrus diseases and will save trees.

Resources for Californians

Please visit CaliforniaCitrusThreat.org for more information on how to stop the spread of deadly citrus disease.

California Law Regarding Citrus Propagation

In California, the collection of any citrus propagative materials, including budwood and seeds, from non-registered sources is illegal. Any citrus trees grown or grafted in California must come from source trees registered with either:

Funding

This article was funded by a grant from California’s Citrus Research Board.

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