At 08:41 AM 10/20/03 -0400, Håkan Bengtsson wrote:
Thanks for your reply. My intent was not to wash the roots just for the
sake of it. I never do. But is good to know in a worst case scenario. I´ve
read in some books and magazines that you should NEVER eliminate more than
1/3 of the soil on a japanese white pine and was wondering if NEVER was a
too strong word.

NEVER is definitely too strong of a word for me since I routinely remove
most if not all the soil from Pinus parviflora when repotting when dormant.

White pines are not easy plants to grow. They regularly die for a host of
reasons, mostly undiagnosed. This situation leads to some pretty bizarre
explanations and cautions. Trying to untangle the reasons is tricky. I have
spent the better part of the last ten years just getting them to grow
reasonably well in our hot dry/cold wet seasonal changes. I have pretty
much solved the problems for growing them HERE, but occasionally, one will
still just up and die on me for no reason that I can discern (surrounded by
healthy plants).

I haven't even gotten around to the finer points of how to ramify them or
to identify the differences in growth patterns between P.p. and P.
thunbergii, since it has been so much work just to keep them alive. One is
also reluctant to experiment on plants that are so valuable and at the same
time so fragile.

I now send out a care sheet with young P.p. grafts, praying that it will be
read. I will copy it below. You may find it instructive.

New Japanese White Pine Grafts

Congratulations. You have purchased some of the finest bonsai starter
material available in the US. These pines have been grafted onto Pinus
thunbergii, Japanese Black Pine right at the root level. This will help you
develop the best nebari possible without using cutting grown material.

These are new grafts, and they need special care. They should stay in these
pots until the appropriate repotting time in winter. They should NOT be
pruned until after they are repotted and then re established in their new
pot. You must resist the urge, pruning will greatly slow down the process
of new root establishment and can kill these young plants.

When you repot you will notice there are not as many roots as with
vigorously growing seedling pines. This is to be expected with new grafts
that recently have had the top of the understock cut off. They need to be
repotted so that they can regenerate their root system in fresh soil that
has not started the composting process (precursor to soil collapse). Do not
use more than 50% fresh bark in your mix, and only use fresh bark or use
100% appropriate inorganic amendments. Soil degradation is a serious
problem in growing Japanese White Pines. Remove all the old soil gently
when repotting. Keep root work to a minimum. More serious root work can be
preformed in later years when your plant is larger and stronger.

These pines cannot tolerate direct intense sunlight in high UV areas or in
hot dry areas. In these situations, grown them under 40% to 50% shadecloth
all day. In milder areas, they will perform best with morning sun and
afternoon shade. If the pots receive direct sunlight (not under shadecloth)
it is recommended that you shield the pots in summer to keep them from
heating up above the ambient air temperature. Root damage from excessively
hot pots is a major cause of White Pine failure.

With a proper soil mix, watering should not be a problem. Water every day
when the daytime temperature is over 80F. Water when needed below that
temperature. Make sure that they cycle wet/dry before rewatering. This is
very important. Fertilize every other week during the growing season with a
soluble 20-20-20, Miracle Gro, Miracid, or other good soluble fertilizer
with minor and trace elements. Fertilize at the full strength recommended
on the label, usually one tablespoon per gallon.


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

http://www.EvergreenGardenworks.com

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