[IBC] Root Pruning, and Top Pruning

Andrew G

Hi everyone.
New to the Newsgroup, and been into Bonsai for about 5yrs.
But recent reading has left me a little confused.
Some books state that when root pruning at end of winter/start of spring, to
also top prune once you have repotted. Equalising the top to the bottom.
However other readings have said to allow a month between root pruning, and
top pruning. With root pruning being first, and doing them too close
together can stress the plant.
Currently I have been lucky, with no losses (touch wood) even though I
pruned at possibly incorrect times.
Anyway, any help would be greatly appreciated.
Andrew
Mid North Coast
New South Wales, Australia.

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Brent Walston

Andrew

So much for the books. This situation points out the dangers of using 'cookbook' solutions rather than understanding the physiology involved. Since the writers of most books are artists first and horticulturists second, the latter often gets short shrift.

Thus it is for the 'rule' that you should top prune the same amount as you root prune. This practice is only for actively growing plants with foliage. The reason is to balance the transpiration to the diminished uptake of water by the impaired (pruned) root system. It doesn't work in dormant root pruning and in fact is counterproductive.

When a deciduous plant is dormant, transpiration is practically zero, so there is no need to 'balance the transpiration'. By removing top growth, you are simply removing the mechanism that the plant needs to grow and form new roots. All those existing buds, especially the terminal buds, just need water to open and form a leaf or set of leaves. They already contain all the food they need. Since this process of bud breaking is occuring at a cool time of the year, once the leaves have formed, transpiration is low, but the plant should still be protected from heat stress until the root system is regenerated.

The terminal bud will not form a shoot until the roots are established again, so the leaves just sit there working away to supply the roots. If you cut off all these buds, you remove this little photosynthesizing factory and force the plant to find food from other tissues to break DORMANT buds, an energy costly process, further weakening the plant.

It's a similar situation for evergreen plants, but you must be aware that there is always more transpiration from evergreens at low temperatures than deciduous plants because of the existence of the leaves, so you have to more careful about protecting them from heat stresses while the roots are growing out. But the principle is the same, it is primarily the leaves (or foliage) that supply the food to grow the roots.


Brent in Northern California
Evergreen Gardenworks USDA Zone 8 Sunset Zone 14
mailto:bonsai@pacific.net
http://www.EvergreenGardenworks.com

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Andrew G

Thanks for the help.

It's sometimes think the reading of books makes it all the more harder, well confusing at least. Amongst books I have, 2 are by the "Koreshofs" sp?, which used to, and may still own a bonsai nursery not too far from here near Sydney. Apparently well known bonsai creators, so certainly books I would/did take advice from.

Anyway, with one book being on Australian Native bonsais, the whole thing with them is mostly critical root pruning during dormancy. Dormancy which happens many times a year for short periods, some natives never going into dormancy and you have to induce it artificially.

I'm a horticulturist, but bonsai offers so much more to learn. As a general rule learnt by Horticulturists here in OZ, Natives do not like the roots disturbed, and never move a native unless it's going to die anyway (e.g it is in the way of something), and even then the transplant will mostly fail.

So I can understand the balance rule when growing. Until now/and reading books I pruned my bonsai, both top and roots usually around Spring. Spring because everything started growing, so the roots would rejuvenate/grow, and I did the top at the same time purely cos I was working on the plant anyway,
and I knew it was going to throw new shoots/get new growth. Natives I have I haven't yet touched the roots. Another general rule with garden plants here is don't prune close to upcoming winter, as the frost will kill new shoots.

The natives don't necessesarily go into dormancy in winter here as the daytime temps are about 20-22 degs cel. I guess my original question was to do with bonsai in general, not just
natives.

Anyway, thanks again for the help, and your advice is greatly appreciated.

Andrew
NSW Australia

John Dhom

Hey Andrew,

IMO what's missing is better context for articles/books. Authors have significantly different philosophy's/culture. There's a pretty radical difference between container culture vs soil culture (in the ground). Further authors subscribe to various philosophies... ancient bonsai purest, new age bonsai experimentalist, horticulturally educated bonsai enthusiast, hortoculturally educated bonsai nurseryman, seed not speed, and so on, and
so on. Wish there was a real list of these categories

I have a Deborah Koreshofs(sp?) book... good book... more from the ancient bonsai purest perspective as I remember it. So, I found it very difficult to digest the articles and books as they are presented from very different perspectives... describing different ways to do bonsai.

Anyone wanna volunteer a name for their primary "philosophy"?

Best,
/jhd

Central Tennessee, USDA zone 6a-6b, Sunset zone 33

Jim Lewis

Hey Andrew,

IMO what's missing is better context for articles/books.
Authors have significantly different philosophy's/culture. There's a pretty radical difference between container culture vs soil culture (in the ground).

Yes and no. Plants grow as plants grow.

Further authors subscribe to various philosophies... ancient bonsai purest, new age bonsai experimentalist, horticulturally educated bonsai enthusiast, hortoculturally educated bonsai nurseryman, seed not speed, and so on, and so on. Wish there was a real list of these categories

I have a Deborah Koreshofs(sp?) book... good book...

Correction: Excellent book, but still not written for bonsai in
YOUR neighborhood, YOUR climate, YOUR water, with Miracle Grow
(or whatever) fertilizer.

Jim Lewis - jklewis@nettally.com - Tallahassee, FL - Wishing that people would remember to snip all the unnecessary OLD stuff from messages.

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************************************************** ******************************
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+++++ Questions? Help? e-mail BONSAI-REQUEST@HOME.EASE.LSOFT.COM +++++