I've was reading brent's article "understanding pruning" trying to come up
with a game plan for training specimens in the ground. specifically one
that is wild and well established. After an initial trunk chop the growth
is course and vigorous becaseu all of those roots in the ground that were
left untouched and were feeding a much bigger tree are now pumping all
their energy to a much smaller one with fewer buds. which is good for
developing a strong leader and creating some thick begginings of
branches . then comes the initial pruning of the roots using a spade aroud
the tree. when would be the best time to do this? I'm thinking mid
summer...when.. as brent puts it.. the tree is shifting gears, and all the
energy up top is now going to go into root production. thus you would get
the best of both worlds... getting all the stored energy from the old root
system.(spring to summer).. and storing all the new energy in a new root
system.(summer through fall) or would it be best to root prune a season or
two before you actually collect.. leaving the larger root system intact for
a while?

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At 05:54 PM 5/22/03 -0400, Steve Wolfinger wrote:
I've was reading brent's article "understanding pruning" trying to come up
with a game plan for training specimens in the ground. specifically one
that is wild and well established. After an initial trunk chop the growth
is course and vigorous becaseu all of those roots in the ground that were
left untouched and were feeding a much bigger tree are now pumping all
their energy to a much smaller one with fewer buds. which is good for
developing a strong leader and creating some thick begginings of
branches . then comes the initial pruning of the roots using a spade aroud
the tree. when would be the best time to do this? I'm thinking mid
summer...when.. as brent puts it.. the tree is shifting gears, and all the
energy up top is now going to go into root production. thus you would get
the best of both worlds... getting all the stored energy from the old root
system.(spring to summer).. and storing all the new energy in a new root
system.(summer through fall) or would it be best to root prune a season or
two before you actually collect.. leaving the larger root system intact for
a while?

Steve

I wouldn't do it in summer. Your reasoning ignores the fact that the tree
is in full leaf and actively growing. Pruning the roots now will probably
throw the tree into transpiration deficit and shock. It DID have a lot of
roots at the beginning of the season and that energy did go to all the new
growth you are seeing, BUT, by now, the new growth is linked to its own set
of roots by separate pathways. The excess root storage and water transport
capacity has been effectively walled off and is unavailable. Water is the
most critical element during summer.

Just let it grow wild and root prune normally in winter, without top
pruning. Or you can begin hedging it now to create more compact growth and
more terminal buds and root prune in winter. The more terminal buds you
grow now, the more push you get for root recovery next spring after winter
root pruning. Buds store their own food, they only need water to open.
Since there is no foliage (deciduous plants) in winter there is no
transpiration deficit after root pruning. You have a very long recovery
period for the roots as the leaves slowly open in the spring. As the leaves
open, root growth will explode in the spring and the entire root system
will regenerate in just a few weeks. Then you will have a balanced system
again, a nice compact plant with a new compact root system.

This is a scheme for 'harvesting' your trees and moving them back into
containers. If you are talking about leaving them in the ground for more
trunk development, taper, etc. I wouldn't root prune at all. I think this
is an overblown concept, usually unnecessary, and needlessly slows down the
growth. Of course it depends on the species, but I find that most of the
deciduous species we use for bonsai can be harvested successfully after
years of growing without any prior root pruning whatsover. If it is to have
any benefit at all, it should be done early in the growing process to
develop fine roots close to the trunk, but these roots don't die, there is
no point in doing it repeatedly. One way to avoid it althogether is to use
the "escape technique", where you simply grow your plant out in a pot and
then allow the roots to escape the drain holes. You harvest by simply
severing the roots with an axe and walk away with an already intact fine
root system. of course, you still have to do the final top work a year
before removing them. You continue to water THROUGH the pot. I have grown
hundreds of trees this way. Little or no difference in trunk development
time over ground planting.



Brent in Northern California
Evergreen Gardenworks USDA Zone 8 Sunset Zone 14

http://www.EvergreenGardenworks.com

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+++++ Questions? Help? e-mail +++++