Which Species Fatten Trunks in a Bonsai Pot?
Growing plants for bonsai tends to assume time in a large training container, or the ground. The goal is to grow a big trunk.
In most cases, this is exactly the right idea. A proportionally larger amount soil grows the large root system that pushes biomass upstairs in trunk girth and big branches.
The goldfish analogy is useful. If you have a 2” goldfish and you put it in a big tank, the fish will grow big. If you keep the 2” goldfish in a tiny bowl, it isn’t going to grow at all. No matter how much food you throw at it (apologies to Dr. Seuss, who was right about everything else).
But once we look at species, there are real differences in those that trunk up well in a bonsai pot.
Here’s a Wisteria in a pot. (A Warren Hill bonsai, incidentally.)
Here the trunk has doubled in a couple decades. It’s always been grown in a pot. The base development is fast even for a deciduous tree, but for a vine it’s extraordinary.
Plants fatten at different rates in pots. Here are some observations:
- in a very small pot, nothing fattens
- once in a bonsai pot, some plant’s trunks will bulk up, others don’t
- Spruce, especially Ezo spruce, seems the least willing to put on trunk size in a proportional bonsai pot, also, Hinoki
- Juniper is famously slow in a small pot
- Black Pine has modest trunk gains in a pot
- Larch is fast
- Wisteria will trunk up in a bonsai pot, which is odd as it is a vine (generally among the most resistant to trunk up)
- Hornbeam and Beech are slow
- Trident is fast to trunk up
- Styrax is about the same as Trident Maple
- Stewartia is slow, half the speed of a Trident Maple
- Atlas cedar is also slow to trunk up
This is all to say that one container size for growing all species of plant may not be optimal, if you are into growing young plants in pots. Once in a bonsai pot, some species do get trunky over time. For others, that caliper rate is glacial.
August 2024 Bulletin
- Tune your cars or book a plane or hovercraft for the Pacific Bonsai Expo in Oakland, CA, October 26-27, 2024, which will be a terrific bonsai party. Hope to see you all there.
9 Comments
As always… very informative info. Makes me wonder, what are some of the most successful ways to fatten different species in a short time while still training and ramifying?
As a side note… Bitch’n Wisteria!
Hi Michael, that might be worth a blog post in itself… There is the accepted technique of growing off the top of the tree to develop taper and nebari at the same time as, for instance a black pine, decandling the lower branches. If you get the energy balance right it can work, but the fact is, it’s not easy in a pot. Often the top gets too strong and then you minimize the bottom without meaning to. That is, if you’re pushing the top and nibbling the bottom, the tree will eventually get the hint and weaken or kill off the bottom branches… But, it can be done successfully with annual pruning of the top part to new smaller leaders.
Can you comment on tropicals?
Hi Dave,
I’m not a tropical expert. If anyone wants to chime in, please do!
Amazing post Michael and thank you for sharing !
So let me get this straight – styrax fattens up in pots like trident , heals wounds almost to invisibility like Stewartia – then why don’t we see styrax anywhere ? To my novice eyes – looks like a missed opportunity in US
Hi Abhidhek—- Styrax…yes, that would seem to be marks in its favor! I think they are underused. In Japan you see a few but it clearly has not be a prime species, more like a 2nd or 3rd rank species. But given the old ones we see (I did a blog post with old styraxes) maybe they are due for their rightful place.
I’ll chime in on tropicals. Some advice on wisteria. I have 4 chinese wisteria on my patio fence. I made the mistake of fertilizing the roots two years ago. My wisteria will grab anyone who walks close enough. I have had to trim these guys back every couple of days. The growth rate is incredible. Moral: I swear that I’ll never fertilize another wisteria. As to tropicals, I have great luck with benjamina ficus, green island ficus fig trees, dracaena, and others. they are very sensitive to light. My fiddle leaf fig will burn if it gets 8 hours of sun.
I forgot my anthuria. Their tricky with water. I water them once a week.
Hi Michael, that was a great read. Could you share your thoughts and experience about fattening up Japanese maples in pots please?
Thank you,
Alex