Marcotting or Air Layering to produce new fruit trees

[Lissa]

Joseph has been studying marcotting and visited my garden to practice on my mature fruit trees, his (Mums') still being a little small.

We found it tricky to source upright branches close enough to the ground to work on and ended up doing two marcots, one each on the Wampi and Soursop (see pics below).

Below is a description of marcotting from the Archives of the Rare Fruit Council of Australia:

Marcotting is one of the oldest forms of plant propagation and is used extensively in South East Asia, notably Thailand, for fruit trees. In Australia its major usage is for litchis.

The criteria for marcotting are far less stringent than for grafting, the main essential being good healthy stock.

Morning, around 9 am, is the best time, providing there has been no rain.

Select a good branch, about finger thick and near vertical.

1. Remove a ring of bark 3 to 5 cm (the article actually says 30 to 50cm but I think this must be a typo) long from a position 400-600 mm from the tip of the branch. The cut must be deep enough to get through the cambium layer. Scrape the branch well to remove the soft material.

2. Dust the cut area with a growth hormone powder, making sure all excess is removed by tapping and blowing, otherwise burns will occur.

3. Take a handful of wet peat moss (we used coir), squeeze out well and place in the middle of a piece of plastic around 250 mm square.

4. Place this around the ringbarked area, tying first the bottom, firming down the peat moss and tying the top.

After 5-6 weeks a good root system should be visible and the marcot is then ready to be taken from the parent tree. This is best done by cutting halfway through and waiting two weeks before completing the cut.

Care must be taken in planting the marcot. In the first place, do not plant with a large ball of peat moss adhering to the roots as this will give rise to fungus; rather, eliminate as much as possible without damaging the young roots.

The marcot should be planted in good potting mixture, well-drained, taking care not to plant too deeply. Ideally, the top of the roots should be level with or slightly above the ground. The plant should be well staked and watered carefully.

Preparing marcot - ring of bark removed	The marcot prepared with peat moss and covering

John answered a series of questions following his talk:

Q. Do you ever add more water to the peat moss?

A. Yes, when they have to stay on the tree a long time; after six months, add water from a hypodermic syringe.

Q. At what time of the year should you marcot?

A. Not during winter or a heavy wet season.

Q. Can you give us an idea of the different kinds of marcotting you have done successfully?

A. Most trees - except coconuts. Most trees are marcotted in Thailand, including guavas and mangoes.

Q. Should you use any special potting mixture when transplanting the marcot?

A. The standard mixture is as good as any, i.e. 1/3 soil, 1/3 peat, 1/3 coarse river sand. Provide good drainage, do not over-water and do not plant too deeply.

Q. Is there any advantage in mixing liquid rooting mixture in with the peat?

A. None.

Q. Do you add any fertilizer when initially transplanting?

A. This can be one of the main killers of plants. Do not add any fertilizer until the marcot shows some signs of growth. The plant only needs fertilizer if it is growing. There is a number of slow-release fertilizers on the market and these are a lot safer than the highly soluble types.

Q. How do marcots stand up to wind when they have no tap root?

A. Seedlings definitely stand up to drought conditions better because they have tap roots, whereas the marcot has mostly surface roots, which must be kept moist. Once a marcot becomes well-established after 6 to 8 years, it can look after itself pretty well, but they need more watering than a seedling during the first few years.

Q. How much of the stem do you chop off below the roots?

A. Not very close to the roots, about 3-4" (8 to 10cm)below, as this is a temporary water supply for the marcot itself.

John Marshall

DATE: May 1981

What Happens at the Air Layer Site

The removal of the bark, cambium, and phloem, but not the xylem, prevents carbohydrates and photosynthates from flowing down the trunk past the girdling site but still allows water and mineral nutrients to flow upward to the leaves.

This keeps the leafy portions of the shoot from drying out and maintains them with an adequate supply of nutrients. The removal of the actively growing cambium layer prevents the regeneration of phloem and healing over of the wound. Because of this the carbohydrates and photosynthates flowing down the trunk collect at the girdling site. The presence of these excesses of carbohydrates and photosynthates (esp. auxin) at the girdling site, plus the presence of the water in the sphagnum moss, causes dormant adventitious buds in the area to grow into roots. When there are enough roots to sustain the shoot independently the shoot is cut off of the tree and then planted or potted.

Below: Joseph using the secatuers to cut through the cambium and phloem layers. He aims to remove a section of bark approximately 4cm long, just below a node.

Joseph used plier to work off the layer of bark then a sharp stanley knife to scrape away any remnants of the cambium layer, being careful to not nick into the woody section which carries water to the portion of plant being marcotted.

Feeling for any remaining (slippery) bits of cambium.

Dusting with rooting hormone. Joseph dusts at the cut end where the roots will emerge.

A plastic bag was packed with moist coir (spagnum can also be used) and, helped by Matt, secured around the marcott using sticky tape and string.

The finished marcott. We couldn't find an upright branch within easy reach, so hoping this horizontal branch will still develop roots in 5 to 6weeks.

[Florence]

Just added a couple of follow widgets to my homepage too to make things easier :)

[Florence]

Lissa, there's a grey "follow" button on the bottom right hand corner of the browser when you're on the blog's home page and not logged in as a wordpress user.  Here's some info https://en.support.wordpress.com/subscriptions-and-newsletters/

Maybe if I succeed a few more times, I can call myself the resident amateur :P

Do post how you do yours Stephen, so we call all learn :)

[Stephen Choi]

Has been years since I have done this. Produces a clone of the tree you are marcotting from. Thanks for reminding me.

[Lissa]

I want to subscribe to your Wordpress blogs but can't see how Florence. I see you have a link to mine there and I would like to return the favour....if I could figure out how it works lol.

[Lissa]

Well done for succeeding! You are now our resident expert ;)

There were three of us trying to secure the medium with the bag and it was still difficult to achieve! None of mine were successful. Needs a bit more study but at the moment I just don't need to be doing any more propagating.

[Florence]

Update ~ I did check my crabappe a couple of month later, but didn't feel any roots so I left them.  I removed the bags today to prepare for repot, and discovered roots!! I've blogged it here

I actually did try one on a peach tree at my parents after the crabapple, but the bag fell off before the roots formed, but there were big  callus tissue.  I think my biggest problem is securing the rooting medium on the tree... 

[Florence]

I mean too thick.. not think.. 

[Florence]

I used coconut coir for the rooting medium, and bubble wrap for two, and a packaging ziplock bag, so I think the plastic should hold, but I suspect I didn't have enough coir in the bubble wrap coz I found the bubble wrap a bit too think and not easy to wrap ... perhaps they're better for bigger branches..I think a scrapped off the cambium layer too, I thought that's what you're suppose to do so it doesn't heal before rooting...

[Lissa]

Aha. Will wait for the update :)

[Joseph]

I managed to get two to start rooting but the layers died. :( I discovered some new info which contradicted what I read before. Rooting occurs in the cambium layer (the green layer beneath the bark) so I've been scraping that completely away to expose the sapwood, which is wrong. I'll try again but at the moment all the lychees and longans are flowering so I can't find a suitable branch to use.