What is Air Layering or Marcotting?
Producing more plants is known as propagation. One very effective way of doing this, is by marcotting also called air layering. Marcotting is a method of asexual propagation. The new plant is a clone of the original. This is not very difficult, it takes practice that's all. You can do it!
How to do it
To make an air layer or marcot, simply select a vertical branch from a tree and girdle the branch.
Next, be certain to scrape away all around the girdle to remove the cambium layer. Now apply rooting hormone gel, liquid or powder. Wrap the branch in moist sphagnum moss or coarse coconut fiber. Take the sphagnum or coir and wrap securely with plastic wrap. The next step is to wrap aluminum foil around the moist sphagnum or coir. Now take your potted air layered plant and move it to a bright but partly shaded area. You want filtered light to reach your plant. The light reaching the leaves, helps the plant to develop roots at the upper region of the girdle.
Why does it produce roots on the branch at the girdle?
The Transportation Superhighway:
All of the food, water, and nutrients provided to plants moves via the phloem. This is an area of the tree beneath the bark of dicotyledonous trees (embryo with two cotyledons).
This vascular tissue, transports carbohydrates and other compounds downwards from the leaves above the girdle to the lower parts of the plant. These carbohydrates are the result of photosynthesis. Those leaves are solar panels that produce sugar/carbs aka energy.
The removal of the bark, cambium, and phloem, stops carbohydrates from moving down the trunk past the girdling site. Water and minerals can still flow upwards via the xylem to the canopy, keeping the tree from dying. When an air layer is made, the xylem layer is not removed and the plant transports water and nutrients upwards. Yes, I repeated myself so it is clear in your mind!
When the girdled area is scraped thoroughly, it removes the actively growing cambium layer preventing the regeneration of phloem. This keeps the wound from healing. Carbohydrates can still flow downward and collect at the base of the girdle. This accumulation of carbohydrates and hormones (auxins) at the girdling site is the key to a new plant developing from the branch. So long as the sphagnum moss is maintained moist, dormant adventitious buds in the area at the top of the girdle will grow new roots. When the air layer has enough roots to sustain the shoot independently the shoot is cut off to be potted and nursed carefully into a new tree.
But wait, girdling kills trees right?
The moist sphagnum/coir keeps the branch from dying because a girdle can kill the entire tree if performed on the main trunk and allowed to dry out. As a matter of fact a girdle or ring barking is used to kill trees by foresters and lumberjacks.
Girdling or Ring Barking is a slow death. One thing that could save the tree from death is the cambium layer. Leaving just a slight connection of the cambium in the girdle will allow the tree to regrow it's bark heal the wound and survive. That is why when air layering the cambium is thoroughly scraped away. A pair of channellock pliers works great!
For an air layer to be successful a few things need to be kept in mind
Not all trees will air layer. Many will but it can take a long time. For example the Jabuticaba or Brazilian Grape Tree can be air layered but has been known to take a year or longer.
Lychees, Longans, Guava, Loquats, Fig Trees are typically propagated by air layers/marcots.
Final tips before potting your air layer/marcot
Check your air layer after five or six weeks, to see if you have a good root system developed. Is it nice and moist? Spray some water if needed. Some trees can take three months or longer. Cut your well rooted branch from the parent tree. Be careful when planting the marcot. Some people remove the sphagnum and others don't! They take as much off as possible and are cautious to not damage the new roots. For me it seems to work either way and I hate risking damage to those roots. In case you do remove those roots, let your marcot sit in a bucket of water for 15 minutes and remove the sphagnum, easier that way. Removing the sphagnum may help prevent fungal diseases from attacking your young root ball. This also helps eliminate air pockets from the sphagnum moss.
How to do it
To make an air layer or marcot, simply select a vertical branch from a tree and girdle the branch.
Next, be certain to scrape away all around the girdle to remove the cambium layer. Now apply rooting hormone gel, liquid or powder. Wrap the branch in moist sphagnum moss or coarse coconut fiber. Take the sphagnum or coir and wrap securely with plastic wrap. The next step is to wrap aluminum foil around the moist sphagnum or coir. Now take your potted air layered plant and move it to a bright but partly shaded area. You want filtered light to reach your plant. The light reaching the leaves, helps the plant to develop roots at the upper region of the girdle.
Why does it produce roots on the branch at the girdle?
The Transportation Superhighway:
All of the food, water, and nutrients provided to plants moves via the phloem. This is an area of the tree beneath the bark of dicotyledonous trees (embryo with two cotyledons).
This vascular tissue, transports carbohydrates and other compounds downwards from the leaves above the girdle to the lower parts of the plant. These carbohydrates are the result of photosynthesis. Those leaves are solar panels that produce sugar/carbs aka energy.
The removal of the bark, cambium, and phloem, stops carbohydrates from moving down the trunk past the girdling site. Water and minerals can still flow upwards via the xylem to the canopy, keeping the tree from dying. When an air layer is made, the xylem layer is not removed and the plant transports water and nutrients upwards. Yes, I repeated myself so it is clear in your mind!
When the girdled area is scraped thoroughly, it removes the actively growing cambium layer preventing the regeneration of phloem. This keeps the wound from healing. Carbohydrates can still flow downward and collect at the base of the girdle. This accumulation of carbohydrates and hormones (auxins) at the girdling site is the key to a new plant developing from the branch. So long as the sphagnum moss is maintained moist, dormant adventitious buds in the area at the top of the girdle will grow new roots. When the air layer has enough roots to sustain the shoot independently the shoot is cut off to be potted and nursed carefully into a new tree.
But wait, girdling kills trees right?
The moist sphagnum/coir keeps the branch from dying because a girdle can kill the entire tree if performed on the main trunk and allowed to dry out. As a matter of fact a girdle or ring barking is used to kill trees by foresters and lumberjacks.
Girdling or Ring Barking is a slow death. One thing that could save the tree from death is the cambium layer. Leaving just a slight connection of the cambium in the girdle will allow the tree to regrow it's bark heal the wound and survive. That is why when air layering the cambium is thoroughly scraped away. A pair of channellock pliers works great!
For an air layer to be successful a few things need to be kept in mind
- Sphagnum moss or coir must be moist and not dry out
- * Branches that don't get sun will not produce roots
- Don't use horizontal branches!
- Make sure you scraped away all the cambium
Not all trees will air layer. Many will but it can take a long time. For example the Jabuticaba or Brazilian Grape Tree can be air layered but has been known to take a year or longer.
Lychees, Longans, Guava, Loquats, Fig Trees are typically propagated by air layers/marcots.
Final tips before potting your air layer/marcot
Check your air layer after five or six weeks, to see if you have a good root system developed. Is it nice and moist? Spray some water if needed. Some trees can take three months or longer. Cut your well rooted branch from the parent tree. Be careful when planting the marcot. Some people remove the sphagnum and others don't! They take as much off as possible and are cautious to not damage the new roots. For me it seems to work either way and I hate risking damage to those roots. In case you do remove those roots, let your marcot sit in a bucket of water for 15 minutes and remove the sphagnum, easier that way. Removing the sphagnum may help prevent fungal diseases from attacking your young root ball. This also helps eliminate air pockets from the sphagnum moss.
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How to air layer a tree part 1 (Baobab)
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How to air layer a tree part 2 (Baobab)
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In this first video.
I demonstrate air layering a Baobab and it had no leaves at all at the time. The tree was still dormant. Don't try this at home people. I am conducting an experiment. Without leaves the tree may have a poor chance of producing roots or surviving.
No leaves to absorb light and utilize photosynthesis to produce carbohydrates! My goal is that the tree will want to survive in response to the wound. I believe (hope) that it will push out leaves quickly in order to survive. The tree may also, somehow absorb light via the bark. Sounds a bit crazy I know!
I demonstrate air layering a Baobab and it had no leaves at all at the time. The tree was still dormant. Don't try this at home people. I am conducting an experiment. Without leaves the tree may have a poor chance of producing roots or surviving.
No leaves to absorb light and utilize photosynthesis to produce carbohydrates! My goal is that the tree will want to survive in response to the wound. I believe (hope) that it will push out leaves quickly in order to survive. The tree may also, somehow absorb light via the bark. Sounds a bit crazy I know!
