Repotting Old Chojubai
Every few years Chojubai need repotting. And for Chojubai, the size of the pot often determines when that is.
This specimen is like many Chojubai in larger pots—they can waltz along for years without getting root bound. In a small pot they will tighten up in 2-3 years. But in a large pot they can take a while. (Unlike a maple, which can get root bound in any size pot while you take a tea break.)
Once the soil near the pot lip resists a chopstick’s poke, then they’re ready. This is the dumb person’s way of doing it, and that’s why it works so well for me. No need to remember if it drained well or not last summer.
A Chojubai in need of repotting, the soil near the pot wall resisting a chopstick’s poke.
Closeup of the operation site.
This pot, though not antique, has a healthy layer of patina on it. A few scratches are visible on the lip, to the left, exposing the much lighter glaze underneath. We are careful with such pots. The cloth underneath was for putting our wires in, when the pot was turned over on that delicate patinaed lip.
Carmen and Masaki adjusting positioning. (Masaki sporting our local brand.)
Masaki tightening down the wires over the bamboo. Notice the cloth over the lip of the pot. Easy to scratch off patina with a tool.
Final placement, with tie-down wires tightened.
Repotting complete. Shredded sphagnum covers the new soil media. The mound helps with the challenges of growing in a shallow pot. More on that next week…
Isn’t it better to shovel it in the summer after defoliating it?
Good question! Yes, for most I do prefer repotting in the summer. But by “most” I mean younger plants. Repotting in June or July assumes defoliation, and I don’t like forcing a Chojubai as old as this one into regrowing.
Enjoyed your note and pictures. Beautiful tree. Thank you Michael.Betty Lou Lages
Did I miss something? Who’s Masaki?
One of our volunteers!
Bought the book and love it!
Two quick questions if I may:
What’s the soil media of choice?
How long is it safe to work the rootball with the tree out of pot?
For Chojubai I prefer 1 part pumice, 1 part akadama. 1/8”- 1/4” size.
We spray the roots often if the work takes longer than 10 minutes. A dry day can be more work with the sprayer. A pine is less needy with misting.
Hi, I transplanted my old shohin into a 3″ deep pot but the root ball is less about 1/4” to the pot wall, could this cause horticultural issues? It is easier for me to water deeper pots!
Yes, you may wish to put it in a wider pot in the future, that 1/4” can get full of roots in a year. Definitely easier to water deeper pots, yes!
I’m relatively new to bonsai and managed to acquire a young chojubai here in Australia.
It’s currently Autumn and I’m just wondering what the plant should be doing when it’s time to repot?
The weather here has turned, no more hot days. But its fluctuating between 17 and 25 degrees Celsius during the day, and 6 and 14 at night (no frosts for quite awhile)
My chojubai is starting to go to sleep, but has also started flowering too.
It’s had a not so great year, which I think is due to lack of fertiliser.
Would be so appreciative of your thoughts! Thank you
If the plant is weaker, do take flowers off. That will give it more energy for other things. Usually they bloom around repotting time. Which is earlier than almost everything else you likely have. Another time to repot is in early summer, after the first growth spurt has hardened off. You will need to cut extensions and defoliate the plant to do that, though, so if the year before it was weak, I’d repot in the early spring.
I see, thank you! Early Spring it is then. I hate to cut the flowers off, but I agree it needs to be done this year. I will enjoy them all the more next year.