How To Propagate Citrus Trees: The Top 3 Methods

While we have several citrus trees, we don’t yet have a grapefruit tree. However, we have a friend who has one, and they offered to propagate a new one for us from their tree. The only problem was, we didn’t really know where to start. So, I did some digging around online and found some ways that we can propagate a new grapefruit tree from it.

Propagating citrus trees allow you to grow the same variety and one that will grow faster than seed. Common propagation methods include grafting, rooting a hardwood cutting, and air layering. These all preserve the cultivar, or parent tree’s, genetic material so that the second tree is an exact clone.

So, while we know what propagation is, and the methods to do it, what are the exact benefits and steps for each propagation? Let’s take a closer look.

Benefits of Propagating a Citrus Tree

Propagation refers to the practice of taking a small branch or bud from an established tree to grow a new specimen. There are many reasons to do this instead of starting from seed: 

• Growing a tree from a seed takes too long. Trees grown by propagation reach maturity sooner. This is especially desirable for commercial growers. Propagated trees generally take 2-3 years to mature, while those grown from seed can take 7-15 years.
• Growing from seed introduces genetic uncertainty. The new tree may never fruit, or the fruit may be undesirable. 
• Grafting allows the tree to take on desirable qualities from a specific rootstock. These include resiliency or smaller tree size. 
• Propagating allows you to preserve old varieties. Perhaps a citrus tree is old and frail, but you really like the fruit. Propagate a new tree from its healthy, young growth. 
• Grafting allows you to grow multiple citrus varieties on one tree to save space. This is often called a “fruit cocktail tree” and is great for people with smaller yards (see image below).

How to Propagate a Citrus Tree

There are three common ways to propagate citrus trees: 

1. Grafting
2. Root a Cutting 
3. Air Layering

Grafting is where you take a piece of one tree and stick it on another one so that they grow together. This is a simplified description of the process, of course. 

Rooting a cutting and air layering are similar in that they do not involve a rootstock. 

With both of these techniques, you are encouraging a small branch or twig to grow roots so that it can become a new, separate tree. 

Let’s take a closer look at how to perform each of these three propagation techniques.

1. Grafting a Citrus Tree (T-Bud)

There are many ways to graft a citrus tree, but generally, bud grafting is best for citrus. The T-bud graft is the easiest for beginners, so that’s the method we are going to outline here.

Supplies:

• A sharp knife
• Budding tape

Directions: 

1. Decide what variety of citrus you want to grow. There are so many to choose from!
2. Collect budwood. Do so during the growing season, between April and November. Collect hardened twigs with buds whose bark has started to harden. Do not collect soft cuttings from the tree’s most recent flush of growth. They should be about a foot long and you can store them in a bag in your fridge for up to three months if necessary. If this is your first time grafting, collect extra budwood to accommodate mistakes. 
3. Select your rootstock. This should be a citrus variety that grows well in your climate. The best rootstocks are hardy and disease resistant. A popular citrus rootstock for many varieties is the Trifoliate Orange. 
4. Prepare your rootstock for grafting. Six inches up from the ground, use a sharp knife to cut a one-inch vertical slice through the rootstock’s bark. Make another horizontal cut at the bottom of the cut to form an upside-down T. 
5. Prepare the bud. Using the same knife, cut out a bud from the budwood along with a one-inch slice of wood (same length as the T-cut on the rootstock). Make sure to include both wood and bark in the cut. Smooth edges will heal best. 
6. Complete the graft. Insert the citrus bud up under the flaps you just made in the rootstock’s bark. Make sure to insert it fully. The goal here is to create a connection between the green cambium layers so nutrients can flow from the roots to the new bud. 
7. Wrap the top and bottom of the new graft with budding tape. This holds everything in place and protects the graft as it heals. Do not cover the bud itself! You should remove the budding tape within a month so it doesn’t choke the tree. 
8. Off to the races! Once the new bud has started pushing out a few inches of new growth, continue to train the tree to grow upwards. It should be growing much faster than it would from seed.

Citrus trees heal best from grafting in temperatures between 70°F and 85°F. Outside of these temperatures, the tree prioritizes its energy to survive in the more extreme temperatures rather than healing a wound.

2. Root a Citrus Cutting

When it comes to citrus tree propagation, rooting a cutting is easier than grafting, although you don’t have the benefit of selecting a hardy rootstock.

Supplies:

• A sharp knife or pruning shears
• Rooting hormone (optional but recommended)
• Small pots
• Sterile growing medium such as sphagnum moss

Directions: 

1. Choose your citrus variety.
2. Collect cuttings. These should be small in diameter, but not soft new growths. They must have some bark already, like with the budwood described above. Cuttings should be as thick as a pencil, about a foot long. Cut off any leaves to reduce moisture loss. 
3. Score the bark near the bottom of the cutting. This encourages healing and root growth. 
4. Use rooting hormone if you have it. Cinnamon works in a pinch due to its anti-fungal properties. This helps rooting happen faster and prevents rotting. 
5. Place the cutting in a moist growing medium. Sphagnum moss is nice for growing cuttings because it holds onto moisture well. Make sure the cutting is right-side up!  
6. Wait patiently. It can take a cutting 3-4 weeks to grow roots. Keep the growing medium damp but not soggy. Be sure to keep it out of direct light for now. Make a miniature greenhouse with a plastic bag to increase humidity and avoid exposure to extreme heat or cold.  

You can plant the propagated rooted citrus tree out to soil once the roots have been established, usually after 3-4 weeks. 

3. Air Layering a Citrus Tree

Air layering is similar to rooting a cutting, except you root it before you cut it off the parent tree. This is a great option for propagation if you have regular access to the cultivar, like if it’s on a relative’s property.

Supplies:

• Sharp knife or pruning shears
• Rooting hormone (optional but recommended)
• Sterile growing medium such as sphagnum moss
• Plastic wrap
• Tape

Directions: 

1. Choose a desirable parent tree.
2. Select a suitable branch. Make sure it’s no thicker than your finger. Anything bigger will struggle to adjust once you remove it from the original tree. 
3. Score the bark with a clean knife to reveal the cambium. This aggravates the growth cells and stimulates healing. Score all around the branch, about two to three inches long. 
4. Wrap the scored area with a growing medium like sphagnum moss or coco coir. Use something that’ll hold onto moisture without getting soggy like soil.
5. Optional: Add rooting hormone in with the growing medium. This just speeds up the process. 
6. Wrap up the media to keep it on the branch. This can be done with plastic wrap and tape on either end. Alternatively, if you plan on doing lots of air layering in the future, you could get a hard plastic mold that clips around the branch. 
7. Wait for the roots to grow in. This may take 2-4 weeks. 
8. Cut the branch below the roots. Remove any tape, plastic wrap, and loose growing media. 
9. Plant your citrus tree in its new home! Make sure it gets adequate water as its roots adjust. 

Final Thoughts

While we’re working out some of the details of our grapefruit propagation, I now know of three different ways we can get the job done.

Out of the three methods, I’m going with air layering. While grafting is super cool and can support different citrus varieties on the same tree, the other two choices seem a bit easier of an approach. If I were to prune a cutting first and try to grow it, there’s a chance it could die before any root growth starts. Because the cutting can stay alive on the tree while it grows roots, air layering seems like the best choice for me.

Still, I’d like to try all three of these methods soon and see which one works best (and which is the most fun). Stay tuned for more!