Back to the Intensives:
Winter. This is the repotting Intensive. It's messy. We repot a lot of trees. And, yes, Boon is very precise on exactly how we do it.
The days are the same: Videos and handouts instruction in the morning, physical work in the afternoon.
By the way, the methods we learn are not original with Boon. He didn't make these techniques up. He apprenticed at Kihachi-En, under the Master Kihachiro Kamiya. He had to do everything exactly like Kamiya wanted him to do. Think about it: Kamiya is the Master, and clients and customers bring their trees in to be worked by him. In actuality, he has too many to do, so he has apprentices do most of the work. But, he wants the work to be as good as if he had done it himself. His clients and customers want to pretend it's ALL his work. So, he trains his apprentices to do things exactly as if he had done them. Boon being one of them.
So, being a student of Boon, is really like being a student of Kamiya. It's how this stuff gets passed down...
Ok, potting: We start off learning exactly how to make the clips that hold the screens securely over the holes in the pot. Then, we learn exactly how to measure aluminum wire to wire trees into the pot. Different techniques are used for one hole, two hole, three, and four hole pots.
Likewise, we also learn how to remove the old wire holding the trees in the pots. How to use the sickle to loosen the tree from the pot. How to work the rootball, etc. Putting in a drainage layer, adding new soil, setting the tree into the pot at just the right height, chopsticking the soil in, tapping the pot to settle the soil, tamping it down flat, watering. I just listed the steps, but golly, there's a technique to every one.
Ah, here's a hot topic: Boon Mix. It's his soil mix that many have adapted. Again, Boon says it's not "his" mix. It's as close to the mix he used when he was in Japan. It is: 1/3 akadama, 1/3 lava, 1/3 pumice, and an handful of horticultural charcoal. In Japan, they use "River Sand". Japanese "River Sand" isn't the same as our river sand. Japan is a volcanic country, so their river sand is a volcanic product rather than a silica based rock, or even a granite based rock. So, Boon substituted pumice for the River Sand.
Here's the key, it drains extremely quickly, especially when fresh. Roots will grow quickly into it. Over time, the akadama breaks down. Root growth slows. Think about it. This is exactly what we want! After repotting, we want the roots to get re-established in the new soil quickly. But once there, we'd like them to slow down so we don't have to be continuously repotting.
You can vary the proportions of the Boon Mix. The basic mix above is great for conifers. Maples have broad leaves and require more water to be retained. Use more akadama. It holds more water than the other two ingredients. Some choose to use akadama exclusively. That works, too.
The mix is sifted. The largest size is the drainage layer. Then the regular size mix. Then topped with the smaller mix for the surface. (If that's what you want.) Chopped spaghnum moss may be added to the surface, too. Especially for those water loving maples. Shohin trees get the smaller mix.
As you can imagine, it gets pretty messy at repotting time. Boon spreads out tarps in his workshop. At the end of the day, the tarps get emptied into the trash or recycle bin. Makes clean up easier.
Really big trees sometimes take a team to repot. To work the bottoms of the rootball, the trees are laid on their sides. One person holds the trunk, which is hanging out off the edge of the worktable. That way, no branches get damaged. The other person works the bottom of the root ball.
The bottom of the rootball is scraped with a 3 prong rake to loosen the circling roots off the bottom. Once loosened, the bottom of the rootball is sheared off flat. Any heavy roots are cut back. Once that's done, the tree is allowed to sit back up right, and the top and sides of the rootball are worked. Using either bent tip tweezers or a root hook, the surface roots are raked from the trunk towards the edge of the rootball. Any circling roots are removed. There should be an slight slope from the trunk down to the edge of the rootball.
The sides of the rootball are worked last. Position the tree so that the edge of the rootball hangs over the edge of the work table. Put a bin under that to catch a lot of the soil that will be removed. Then using the bent tip tweezers, carefully tease out the roots, and remove old soil, always working from the inside out to the edge. Cut back until you have removed as much soil as you think necessary, all around the tree. Then, an important step: Tease out about 1/4 to 1/2 inch of feeder roots, leaving them exposed. The prepared root ball should be "fuzzy" all around. But NOT on the bottom.
When the tree is placed in the pot and new soil is added, these fuzzy roots will get chopsticked with new soil, and will actually already be in the new soil. So, they're ready to grow. You see, roots like the soil they're in. If they're in a compacted soil, and there's loose soil right next to them, they might not grow into the loose soil, choosing to remain in the compacted soil! That's also why we don't tease out the bottom. We don't want roots to grow on the bottom. We want root to grow OUT, not down. So, the fuzzy roots are already surrounded by the fresh soil, so they'll start to grow quickly.
Then water until the water runs clear, then right back out into the sun! Boon doesn't set the trees in pans of water to soak. He wants the fine particles to be washed out.
There's more needle pulling and wiring.
That will be in a future post!