Air layering is a way to propagate the tree without growing it from seed or cuttings. Air layering is when you take a tree that is already established, remove part of the bark, and surround it with peat moss.
After a while, the roots will develop in that location allowing you to separate that part of the tree and plant it separately.
This method is great not only because you can get a new tree to establish pretty quickly, but also because you can choose the best part of the tree for your bonsai.
A lot of times you’ll find a tree that has great movement and curves at the top and you know that this top part would be perfect for bonsai. With air layering, you can take just that top part and grow it independently creating a beautiful bonsai.
For this air layering tutorial, we are using a Brazilian Rain Tree, the scientific name Pithecellobium tortum.
Items you will need:
- Sphagnum Moss – Naturally long fibers of this moss make it ideal for air layering technique. It holds up to 20 times its weight in water. You will use it to wrap the bark and help promote the root development.
- Concave Branch Cutter – Needed to cut spikes and branches.
- Sharp Shears – Needed for trimming branches.
- Aluminum foil – You will need it to hold the moss in place when you place it around the tree. Any kind will work. Foil holds moss close to the trunk allowing for the water to get in and at the same time giving some room for air movement. You can also use a plastic bag.
- Sharp knife – You will use it for cutting the bark. It can be a grafting knife or a pocket knife.
- Bucket of water – You will use it to soak the moss before placing it around the trunk.
- Rubber gloves – Sometimes moss can contain flesh-eating bacteria, so you want to wear gloves for protection.
Here is a step-by-step video
Step 1: Soak moss in water
Place a handful of moss in the bucket with cold water, so it can soak while you are working on the tree.
Step 2: Trim branches and spikes
The Brasilian Rain Tree is used for this air layering technique. First, find the area that you want your new tree to start from. Next, trim small branches and sharp spikes around it so you have easier access the that area.
Step 3: Peel the bark
Score across the bark with a sharp knife all around the trunk of the tree. Cut deep enough till you hit the hardwood. Since this tree has a flattened trunk, it is a little more difficult to do. Next, come down a 1-1 1/2 inch and repeat the process.
You are trying to cut enough bark so there is enough space for the roots to grow. If there is not enough separation, the bark will heal and the roots will not have enough space for growing.
Then, score down the middle connecting both rings, and peel the bark away from the trunk. You want to have a straight bottom line all around the trunk.
Step 4: Apply the moss
Squeeze water out of the moss. Spread moss onto the piece of foil and place it around the wound.
You want to make sure the foil is nicely folded around the trunk. It doesn’t have to be too tight. It is ok if there is some space in between. The main goal of the foil is to hold moss close to the trunk.
Keep the foil on for 1 or 2 months. Every few weeks peel back the foil and check if the roots have developed. When you see that roots have developed, you can cut the tree. Here you can see the roots after one month.
As you can see, the roots start at the base of the cut and go all the way down to the bottom of the wound. So, when you cut down the tree and plant it, these roots will support the growth and development of the new tree. Here is how the tree looks after it was cut down, planted, and left to develop for one year.
It is probably hard to imagine this tree can be turned into a beautiful bonsai, but here is a photo of this tree after it was repotted into a bonsai pot, root pruned, and styled.
You can see a HUGE difference. I have a step-by-step tutorial on how to turn this pre-bonsai material into a beautiful Brazilian Rain Tree Bonsai.