Bonsai Tonight

Pinching spring candles on black pine

Posted in Bonsai Development by Jonas Dupuich on March 31, 2015

The basic premise behind developing material for bonsai is straightforward: first build the trunk, then focus on the branches. When building the trunk, encourage vigorous growth to thicken the trunk rapidly. When focusing on branch development, encourage less vigorous growth to ensure good branch density. Sounds easy, but there may be a bit more to it than that. When making the transition from trunk development to branch development, many bonsai will be quite vigorous. What are some good strategies for decreasing vigor? A reduction of fertilizer sounds like a good idea, but reducing it too much can weaken trees. And when developing pines, it’s important to keep them strong enough to withstand decandling. Reducing sunlight or water is another strategy, but to keep trees healthy, plenty of sunlight and water are required. The main thing is to avoid over-watering at this stage as it can lead to excessively long needles. One way to slow down pines is to shorten the spring candles. After the candles begin to elongate, simply break off some portion of the candle with your fingers. How much to break off depends on how long the candles are. Here’s an example on an 11 year-old black pine. Young black pine

11 year-old black pine

The idea for this pine is to make a small-sized bonsai. As the trunk has reached the desired size, I can pinch the longer candles to reduce the amount of food the pine produces. Pinching a candle

First grab the section to be removed

Pinching a candle

Then snap it off

I shortened the longest candles on this pine by about half, but left the shorter candles alone. Young black pine

After reducing the longest candles

I could have reduced the longer ones a bit more, but I didn’t want to remove too much foliage at this point as I’ll have another opportunity to balance vigor come decandling time. Do note, candle pinching is distinct from what is commonly referred to as decandling. Whereas decandling is the removal of fully developed shoots in spring, pinching refers to the partial reduction of candles before the needles elongate. Once pines are further developed, it’s more rare for extra-long candles to develop as the vigor is generally better balanced in more mature trees. When these long shoots do show up, I snap them off.

Today marks post #600 – thanks for reading!

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Feed me!

Posted in Bonsai Development by Jonas Dupuich on March 13, 2015

What’s wrong with this picture?

Cork bark black pine

Cork bark black pine

The tree is growing, but there is no sign of fertilizer.

Cork bark black pine

With tea bags filled with cottonseed meal

That’s better. The sooner I can start fertilizing, the stronger I can make the tree by decandling time.

I enjoy seeing the male flowers on pine, despite the mess. Here is the tree from the back and sides.

Cork bark black pine

Left side

Cork bark black pine


Cork bark black pine

Right side

I usually start with 1-2 units of fertilizer for small sized trees and 3-4 units for larger trees. I treat young and middle-aged trees the same.

Black pine

11 year-old black pine

Black pine

21 year-old black pine

While it’s more common to hold off on fertilizing deciduous varieties to avoid long internodes and large leaves, I make some exceptions.

Japanese plum

Japanese plum

My plum is the first tree to show signs of growth each year, and if I don’t start feeding quickly, the leaves turn yellow.

Why mention fertilizer so early in the season? Because the sooner fertilizing begins, the more vigor can be produced in a given year. While this can be important for all varieties, it’s especially important for pines that are to be decandled as there’s only so much time between repotting and decandling.

I usually wait three weeks after repotting to begin fertilizing. My standard fertilizers are fish emulsion and cottonseed meal, but this year I’m planning to use a greater variety of fertilizers to ensure the trees get a broader variety of nutrients.

Is it time to start fertilizing in your garden?

Time for a smaller pot

Posted in Bonsai Development by Jonas Dupuich on March 10, 2015

First develop the trunk, then work on the branches. That’s how I think about bonsai development. If the trunk has yet to reach its final size, I use large pots and encourage vigorous growth. When I’m happy with the trunk, I move trees to smaller pots and focus on refinement.

A number of my black pines turn 11 this year. A few have reached the desired trunk size. I’ve been slowly removing large escape branches and am now ready to move the trees to smaller pots.

In general, if the soil is good, it’s easy to use a smaller pot as the root ball will have fine roots throughout. If not, the tree will have to stay in an intermediate-sized pot until enough fine roots develop to support the tree in a smaller space.

Here are two of the 11 year-old pines I repotted this winter – both were container grown.

Black pine

Exposed root black pine – 11 years old

Black pine

After repotting

Black pine

11 year-old black pine

Black pine


After repotting – note how the trunk looks larger in a smaller pot

Yes, Northern California is in the middle of a mild winter and most of my pines are already growing. As I repotted these trees about a month ago, I can start fertilizing now to make sure they’re strong enough to be decandled come spring.

Ever wondered what it’s like to be a bonsai apprentice in Japan? For those who haven’t done so already, feel free to submit questions to Juan Andrade, the Costa Rican bonsai artist studying at Aichi-en in Nagoya, Japan with Junichiro Tanaka, via AMA scheduled for later today (Wednesday Japan time) at Ask Bonsai Tonight.

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Too much of a good thing

Posted in Bonsai Development by Jonas Dupuich on March 6, 2015

As I worked my way through the repotting of many pines this winter, I found a young specimen that’s beginning to take shape. Nice, I thought, it even has a good root base. Then I looked closer.

Black pine

Black pine – 11 years from seed

Up close, I found that the roots were actually a bit much for the tree.

Root base

Surface roots

Is this really a problem? Not necessarily. If the idea is to let the tree grow for another 10 years to thicken the trunk, it would be possible to change the relationship between the trunk and the root base over time. If the idea is to make a shohin bonsai, it would be tricky to find a pot for the tree. I’m not sure where the tree is headed at this point, but for my taste, I prefer the roots to enter the soil closer to the base of the trunk.

Root base

Chopsticks highlight the ratio of trunk to root base

From the side, the ratio of trunk to root spread looked even more out of balance.

Root base

Root base from the side

Root base

Chopsticks indicate the root spread

What to do? One thought is to let the trunk thicken. Another is to slowly reduce the root base. For now, I’ll pursue both options – minor surface root reduction and increased trunk size. That means several more years of vigorous growth for the trunk, and attention to detail during repotting to take what opportunities I can to reduce the root spread a bit.

Would it be ok to to nothing and continue to develop the tree as is? Yes. It could be that the wide root spread could become an interesting feature that makes for a unique tree. After this year’s repotting, I’ll have a few years to think about it.

Black pine

Front – chopsticks indicate root spread

Black pine


The same topic came up during my visit to Mr. Iwakiri’s garden in Japan last year – see “A seedling-cutting with too many roots” for details.

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