Soil and repotting frustrations

Joanie

I began repotting some trees that I purchased last week, particularly maples. Although a few of them were leafed out, the rest were still just beginning to move.

The soil that they were in was incredibly rocky. What looked like smooth, small gravel used to mulch the top was pretty well the entire content of the soil! There were layers (yes, layers) of a soft red volcanic rock in the bottom, but no organics to speak of. Getting the rocks out of the roots was very difficult. Although it isn't a good time to prune roots if the tree has budded out, I went ahead on the trident because there was no way to get into the root mass otherwise.

On the opposite end, one little tree in a 4" pot that I bought at shohin needed repotting. It's a leather-leaf trident, and I only intended to slip it into a larger pot. However, pulling it out, it was apparent that the soil was pure clay with chunks of red rocks. That clay just washed away, but I was surprised that it was so fine (and then just big rocks) and there were no soil ingredients that were between pinhead sized to small pebble sized! Yet the tree was doing all right, somehow. It will sure do better now, in the new mix!

The ume got repotted too. The roots were also full of rocks, gravel, and pebbles. Very little organic. It would never have survived in our climate, where a hot dry summer day can suck the moisture right out of tender leaves. It's much happier now, in a mix of 60% inorganic, 40% organic. The inorganic is primarily perlite, with some pumice and lava thrown in. The organic is composted mulch which doesn't include peat, but has fir bark as it's primary ingredient. (Along with bat guano) The mix is chunky and light, doesn't stick together when squeezed, and will hold enough water to get the roots through a dry California day.

Soil is definitely one of the most overlooked, misunderstood segments of bonsai art. Yet it is crucial to the health of the tree.

Just had to rant.

Joanie

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midwestbonsai

I am always surprised at all of the bonsai "nurseries" and vendors that use a mix like you discribe.
It is too bad that the soil composition is not has focused upon as the styling in the world of bonsai.
-Paul

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bonsaimaniac

soonami

bonsaimaniac, I'm new to Bonsai, but I have to say that now that I'm using proper potting medium, there is a big change in the quality of my trees. Although there might not seem to be much difference, try some different mixtures and you will see some considerable differences.

Knowing how to water is something that is underrated, but soil is very important too. If you have any question about the importance of soil in horticulture, just go to a university library and check out some soil science journals. At Penn, there are shelves and shelves dedicated to soil science and a lot of empirical data collected regarding everything you want to know about soil.

I think the difference between hobbists and masters is the understanding of the impact of soil on the tree. Of course I recognize I know very little about soil other than it is very important

Vonsgardens

Well,
I guess that the trees were apparently flurishing in the soil they were in. The soil mixes we use vary from a little organic to none. Indeed, many Satsuki azaleas are planted in pure kanuma. Why do you believe that a tree in a pot requires organic material in the mix? Indeed many of the very best trees are grown in a mix of akadama-pumice-volcanic- some are grown in pure river sand.

I think that experience in soil choices will certainly provide better results than saying there is only one way to do things. Perhaps you can get together with some of your more expereinced club members and get help for soils that work in your area.

Best of luck with your trees.
John

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Joanie

John, I suspect that this soil worked well for the man who owned them, because he lived in a far wetter area, and only moved here recently. However, there was not as much root growth as you would expect to see. The Japanese maples had very few roots considering how long they had been in their pots. And the rocks and pebbles were primarly smooth, not pumice or lava or akadama.

This was the extreme of what I have seen. Unless these trees were regularly dosed with fertilizers, there was nothing to hold the nutrients for the roots. And I suspect that they weren't dosed with fertilizers often enough.

But I'm not going to argue with you guys.

Joanie

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"You can say any foolish thing to a dog, and the dog will give you a look that says,
'Wow, you're right! I never would've thought of that!'" ~ Dave Barry

Joanie

Oh, and John? I didn't say that there was only one way to do things, and I didn't say that the organics were what held the nutrients. And I've been studying the local soil requirements for a year now, and since everyone has a different mix, philosophy, and result, I'll just go with what works for me.

Joanie

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"You can say any foolish thing to a dog, and the dog will give you a look that says,
'Wow, you're right! I never would've thought of that!'" ~ Dave Barry

bonsaimaniac

Soonami, if you are using a very poor quality soil and switch to a better mix of coarse you will see an improvement. The point is that a good soil is reflected by its ability to contain water and hold fertilizer. The reason that there is no one soil mix that is best is because people are growing trees in different climates. Those in the NW US are going to have a very different thoughts about high organic contents then those in the midwest. You could use the same soil in both places but you would need to shield plants in the northwest or risk root rot. Soil is relative.

All I'm saying is that soil isn't underrated. How many threads are there regarding soil mixes? They far out number those regarding the importance of how and when to feed trees.

OK, my mood to debate has passed Soil is important!!! Just know what your tree's needs are.

mgodbee

I agree climate most likely is the biggest factor, along with watering technique. I have always had pretty large particles in my soil per the advice of those more knowledgeable, but I have slowly downsized the particle size due to the intense summers we get here in Atlanta. They are still kinda large and fast draining, but during the summer, I swear I could water them in the morning, come home from work and they would be dry. I never had serious problems, but it has scared me since, and gone to medium sized particles. Now I still water morning and night in the summer when it is hot, but it is not as drastic, and I don't have to start watering twice a day until Summer rather than mid-April. I would imagine this would not be the case in the pacific northwest. I can't say my trees are worlds better, but it gives me more comfort doing it this way. As for inorganics vs. organics, I started out with little organics like pine bark, but have gone up to anywhere from 25%-50% pine bark for the water retention. I have tried 100% turface as an experiment and I couldn't keep it wet at all down here. I have heard great stories from others using such a mix, but unless you are with your trees all day, it is impossible to me in the summer time. As for Kanuma, I like it, the azelias and Camelia's thrive in it, I have a ficus retusa that I don't really like I tried in straight Kanuma and it has thrived. As for Akadama, I have no use for it. The cheaper Akadama breaks down like no tomorrow for me, and the high-fired seemed to have no impact, in fact the only Juniper I have lost was in straight high-fired Akadama. I won't say it is a poor choice of soil, but not worth the money to me. I am a turface guy. As for my mix, who knows? I change it on a whim and on availability. I use river sand, turface, silica sand, Lava rock mostly, all mixed together with pine bark. I use Kanuma for Camelias and Azaleas mixed with a touch of pine bark. For Bald Cypresses and Willows I use straight up Mushroom compost and oak leaf mulch. No water escaping from that mix...

Unlike most people though, all my trees are full sun, all the time and I have had no problems. Maybe I am lucky, but for me it is logistics, I only have shade in the front yard and I won't keep my trees there.. My maples and Azaleas thrive and I have had no problems. I do use a product called pro-tekt by dynagro, who knows if it works or not, but not having any problems, I will keep using it. At my house, the front yard is heavily shaded on one half and dappled shade or full sun on the other half. My landscaping trees/shrubs are azelias, camelias, boxwoods, and three Jap. red maples (2 Deshojo and I Dissectum). The azalias are all in the shaded part and thrive. One camelia is shaded and one is in full sun and both thrive. I have tons of boxwoods and the ones in the shade look terrible and the ones in the sun thrive. The maples have no preference at all it seems... Anyway, sorry for the long post and my rambling....