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.
Exposed root black pine – 11 years old
11 year-old 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.
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 – 11 years from seed
Up close, I found that the roots were actually a bit much for the tree.
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.
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 from the side
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.
Front – chopsticks indicate root spread
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.
Repotting recently grafted young pines is just like repotting non-grafted pines, only additional care is taken to avoid damaging the union.
Grafted cork bark black pine
After removing the pot
Note the white spot – there are signs of root adelgid infestation. For those curious to see how mycorrhiza differs in appearance from adelgid infestation, see below.
Mycorrhiza – and lots of it
Simply coming out the roots cleared away most of the affected area so I didn’t spray pesticides to address the adelgids.
After combing out the roots
I planted the pine in a colander.
Nestling the tree onto a mound of soil.
Once the tree was in place, I tied it in and added more soil. Using chopsticks, I worked the new soil in between the roots.
Before chopstick work
After chopstick work – notice the level of the soil has dropped
I then added soil to fill the pot and tamped it into place.
Now, one year later, it’s time to repeat the process. Both the scions and their hosts grew well last year, so I need to further reduce the regular black pine foliage to encourage the cork bark foliage.
I began by reducing the branches, leaving only one shoot on each tree. I then removed some needles. When there were branches growing above the scion that might shade it, I removed these branches first. The idea is to slow down the host tree and to provide the scion with as much sunshine as possible. Here’s what the process looked like for three young trees.
Cork bark black pine – 2 years after grafting
I left the grafting tape in place when I removed the grafting bag as it can help keep the scion in place while the union strengthens.
After removing one of the original branches
After removing a second branch
With the branches out of the way, I removed all of the old needles and a few new needles from the last remaining original shoot.
After removing needles
Here’s the same process repeated for two more trees.
2-year old cork bark black pine – the host tree is now five years old
After removing branches
After removing needles
Tree number 3
After removing branches and pulling old needles
Once the the cutback and clean-up was done, I repotted the trees – details next time.