Bonsai Tonight

An educational website about bonsai development

How to create seedling cuttings – Japanese black pine

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I began to describe the steps required to grow Japanese black pine bonsai from seed last year, but left off just after planting the seeds. I ended up abandoning last year’s batch as only a dozen seeds sprouted. I tried again this year with much better luck. Due to a cold spring, the seeds took a long time to sprout. After maybe three months, most of the seeds I’d planted were growing well. It was time to make seedling cuttings.

Young Japanese black pine seedlings

Young pine seedlings

Pine seedlings typically produce a single tap root that reaches downward and grows vigorously to provide a good anchor for the tree. Although they are good for forest trees, tap roots are not as good for young bonsai.

A couple of generations ago, bonsai enthusiasts figured out that cutting the tap root produced a number of lateral roots. As these lateral roots developed, the young trees grew faster, denser, and produced a flared trunk base that is often desired in pine bonsai. Many pine bonsai have been produced in Japan by this technique, and the technique has been gaining popularity in the US for at least 20 years. I first learned about the process from Boon Manakitivipart and Bonsai Today numbers 12 and 20. The techniques below represent knowledge I’ve picked up from Boon, Bonsai Today, and many years of practice – I started my first batch of pine seedlings over 17 years ago.

The basics of the process are simple: make cuttings out of young pine seedlings. I begin by filling a nursery flat with 4″ plastic pots and adding the soil, one layer at a time.

25 pots in a flat

Drainage

Drainage – large lava particles

Bonsai soil

Standard Boon mix – akadama, pumice, and lava

I will plant the pines in a pocket of sand to keep the cuttings moist. I watered the soil and then used the handle of a bonsai trowel to create craters into which I poured fine sand.

Using trowel to make space for sand

Repurposing a bonsai trowel

Ready for the sand

Craters created

Soil mix complete

Craters filled with sand

Once the sand was in place, I again watered the soil and created small holes with large gauge copper wire. When the cuttings are ready, I’ll carefully drop them in these holes.

Creating hole for cutting

Creating space for the cuttings

The next step is creating the cuttings. I begin by carefully uprooting one cutting at a time. I try to use seedlings that are healthy like the one on the right in the photo below. The two seedlings on the left are weak – I did not use them for cuttings.

Seedlings

Two weak seedlings and one healthy seedling

Pine seedling

Healthy pine seedling

There was considerable variation among the uprooted seedlings. Although I typically worked with one at a time, I did a few at once for this photo.

Seedlings

Pine seedlings – time to make the cuttings

I made the cuttings with a razor, leaving about 3/4″ of stem below the first needles. After making the cut, I quickly dropped the plants into water to keep them moist.

Making the cut

The seedling becomes a cutting

Placing cutting in water

Floating around

Cuttings

Plenty of seedling cuttings

Before planting the cuttings, I dip them in powdered root hormone to help the cuttings develop roots.

Applying root horomone

Seedling cutting with root hormone

I approach the planting of the cuttings with care. After setting the cutting in one of the holes I created, I gently pressed on the surrounding sand to close the gap. I tried to move the cutting as little as possible to avoid disturbing the hormone. I also skipped on water when I was done to avoid washing the hormone away.

Seedling cutting complete

Seedling cutting in its new home

One flat down, three to go

The first flat complete

I’ve kept the seedlings outside under shade cloth for the past five weeks. I’m slowly moving them into spots where they get more light, and I’m misting them several times a day – more when it’s hot, less when it’s cool out. That’s the recipe for the time being. Once the seedlings start growing quickly – evidence of new roots – I can begin to fertilize and continue to provide the seedlings with more and more light.

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Comments

  1. It’s nice to see it worked. Would you bother with seedlings though if you weren’t growing them to sell? I used to do cuttings all the time but now just prefer advanced nursery stock, It saves years in training. I am so impatient! Thanks for the post

    • Alex makes really good points. I too like working with more mature trees, but I grow pines from seed because it’s so difficult to find good material. When I start a lot of trees, I am confident that I’ll end up with a few really good ones. I also know that if I don’t start trees from scratch I may never end up with good material. If I were primarily motivated by sales, I’d start a lot more!

  3. I believe the desire to use seedlings is that nursery stock rarely has a good nebari, which is highly prized in JBP, These trees will have nice spreading roots, and a good tree can be developed in ~10 years or so for a shohin. Really good JBP are hard to find in America, so you have to pay a lot of money, or grow your own.

  4. Jonas,

    What is the success rate for the cuttings? I’ve heard of this method before but it is really nice to see the whole process laid out.

    Thanks for the info!

    jeff

    • Hi Jeff – good question! I’ll be happy to share the results when they come in, likely this fall. Generally, a high percentage of the trees make it.

    • Any bonsai soil mix that drains well will work with the seedlings. I’d stick with inorganic mixes with particles smaller than 1/4″.

  7. This is the best way to acquire good bonsai, especially pine. There are very few examples, from nursery stock, suitable for good bonsai. Even with the these examples, there are many issues that need to be corrected. The time spent fixing these problems will equal the time growing JBP from seed; the different is you have total control.

  9. Jonas..The articles you mention – suggest that the optimum time to make the cutting is when the stem of the seedling turns a violet color. Is that correct based on your experience ? Approx. how long since you planted the seeds – until you made the cutings…Tom

    • Hi Tom – I don’t have enough experience to know how much difference the stem color makes when making cuttings, but I’ve noticed that by the time the center bud begins to grow – the time at which I look to make the cuttings – the stem has usually turned red or purple. As for the time from planting the seeds to making cuttings, that’s tricky. Some seeds sprouted early and grew slowly. Others sprouted late but grew quickly. About three months after planting the seeds – much later than I expected – most seedlings were growing and ready for the cutting process.

      As an experiment, I made a dozen cuttings from weak or young seedlings to see what happens. I’m curious to learn what becomes of these and will share the results when I find out.

  10. Thank you for such a clear and concise “tutorial”. I’m intrigued and would like to give it a try myself. One question from this novice: I live on the east coast (Vermont). What would my game plan be for the seedlings during the 1st winter? Should I put them in a greenhouse (35-40 degrees) for 16 weeks with my other trees and allow them to go dormant or do they require a completely different environment?

    Thank you.

    • Hi Richard – I think your idea of protecting the seedlings in a greenhouse that stays above freezing is a good one, and it’s OK that the seedlings go dormant in the first winter. I think the main idea is to protect the seedlings from hard freezes.

    • Hi Alexander, there’s not much news to report – they’ve been growing very slowly! Now that it’s a bit warmer they’re starting to move a little – I’ll post an update once they’ve grown a bit more.