CARE INFORMATION, PART III
This Page Last Updated: October 3, 2011
SOIL MIXES
Coarse for good drainage and oxygen flow for the roots with enough organic matter to retain the proper amount of moisture for
each type of plant and its micro-climate location.
A general-purpose mix would be one part decomposed granite (1/4" minus) or chicken / poultry grit + one part general-purpose
potting soil mix; or
three parts chicken grit + two parts potting soil; or
four parts chicken grit + four parts forest mulch + one part peat moss. For acid-loving plants, switch the last
two ingredients to one part mulch + four parts peat moss.
A recommended mix for conifers would be one part Turface® + one part pine bark mulch + one part pea gravel.
Another pine mix is
one part hard Akadama + one part lava + one part pumice, with 5% of the total mix decomposed granite and 5% charcoal,
all washed and screened down to 1/4 inch.
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WINTERIZATION
Why?
To Moderate the Temperature Fluctuations that We Have
1) Low temperatures between -20° and -10° F (USDA Zone 5).
2) Moisture-withdrawing winds and low humidity.
3) Temperature fluctuations (sometimes up to
70°F during days) which can bring trees out of dormancy before late
winter freezes.
How?
1) Before mid-August: stop fertilizing, especially with high-Nitrogen products.
(For outdoor plants here, regular fertilization is recommended from early May to early August --
"feed weekly weakly".)
2) September: start slowly cutting back on watering to help harden the wood.
3) No heavy pruning after mid-summer, otherwise too much delicate new growth will be stimulated.
4) Thin any thick foliage masses on junipers to allow more light in during winter, then the
new spring buds will be fatter.
5) Pack outdoor bonsai trees to keep an
even
temperature.
Use a non-glazed cold frame/poly frame (can be made with 3/4" galvanized steel and 60+ mil
poly plastic), unheated shed or garage, vented greenhouse,
bottom shelf of a sheltered workbench, a non-southern corner of the house protected from
the wind, the north or east side under a large and protective landscape tree, and/or bury
the bonsai trees still in their pots in the ground.
Then, surround and cover with several inches of some type of mulch (wheat straw, oak leaves, pine
needles, bark, snow, foam peanuts, etc.). (Be aware that in a very small and humid setting,
however, spores on the non-oak mulch leaves could multiply into a potential fungal or other infection for your
bonsai.)
Be careful your trees do not get too long of direct exposure to sunlight
(or snow-reflected sunlight): sun-scald in winter is caused by the heating up of one
side of the tree so that the sap rises prematurely during the day and then is frozen at
night, sometimes resulting in bark splits.
Once deciduous trees have lost their
leaves they can be kept cold and dark. (As soon as deciduous trees start to bud in
late winter/early spring, you will need to put the plants in light --
with temperature protection -- so that the new growth doesn't get too weak and leggy.)
Evergreens probably do not
need some type of light during the daytime.
5) Check regularly and water as needed. Dehydration can quickly happen.
6) Pots most likely to break during the winter are either low-fired terra cotta-like or contain
wet, muddy soil that expands. If during winter a bonsai pot is discovered to have broken/split,
as long as the roots are not exposed, leave until spring and then re-pot. If the roots are
exposed, tie the pot together and mulch around it extra well. Pay extra attention to #4 above.
7) Tropicals brought outside on occasion in the summer need to be kept inside when outdoor nightly
temperatures are consistently in the 50s. Indoor plants need very good LIGHT and
good air-circulation. Be sure they are not too close to the glass of an uninsulated
window. It is recommended to get a small personal-type fan and let it blow across
your indoor trees for a few hours two or three times a week to help keep insects at bay.
Feed indoor plants monthly throughout the winter.
See also this in-depth
Freeze Damage
article.
ROCKY MOUNTAIN WINTER CARE
"Since you may not be familiar with winter care of bonsai
in this area, I should like to mention a few of my numerous bitter experiences.
Colorado has extremely changeable winter weather. The sunny daytime temperature
of 60° F is very fine; but after sunset the temperature has been known to drop
to -0° F to as much as -20° F at midnight. Under these variations, bonsai
in ceramic pots, which are sitting on the ground, cannot take and have not taken the
extra severe changes of the winter climate.
"Some 15 years ago, give or take a few years, I had not known
these facts and, regretfully to this day, lost many beautiful bonsai of untold value.
Still reminiscing, what heart-breaking times for many of us bonsai growers! In
spite of or because of this, we've put our heads together in earnest and furthered
dedicated research. There have been numerous conclusions, the most important
of which is to understand and follow the natural way of forest or field.
"1. Be ready, even as early as September, to winterize bonsai,
since it is always 'later than you think.'
"2. Bury every bonsai in a pot, to be buried in the ground,
up to the rim of the pot in gravel or sand.
"3. Why in gravel or sand? Because either provides
excellent drainage.
"4. Reason: in freezing weather, ground and pot freeze
together; when thawing in mild temperatures, they thaw together.
"5. If bonsai are set on top of the ground or atop
shelves, there may be freezing, then thawing, which would injure the fine root
system inside the pots.
"6. Then, with approaching spring, the root system
invariably cannot regain activity.
"7. To this day, by unsoothed bitter experience in
these areas, I have known a cold snap to occur even the first week in September for
three or four days. One must always be on the alert. Most bonsai must be
protected and covered at night with heavy plastic sheets, which are removed in daytime.
"8. In freezing weather, just let the bonsai alone; do
not water.
"9. During a spell of warmer temperatures, apply water.
"10. Lastly, though mighty important, based on my own
experiences and findings: The first year after planting is not bad, because the root
system has not stretched out too far nor become established inside the pot. In
the second year, many roots will have stretched toward the outer circumference of the
pot. In the third and later years, more roots will have encircled within the pot;
these are the crucial, dangerous years, if bonsai are not buried in the ground in sand
or gravel. I cannot stress this point too much, for I have suffered losses and hope
that you will benefit from my experience and thus be saved some losses."
(George T. Fukuma (1902-1974), Denver, ABS Journal,
Fall 1971, pp. 54-55)
SCHEDULES for the Rocky Mountain & Great Plains Region
Dec - Feb give bonsai winter protection
Mar - midApr acclimate trees for spring conditions
midApr - midAug best time to transplant bonsai
Oct - Nov acclimate trees for winter conditions
May - Jul wire and shape deciduous plants
Dec - Mar wire and shape evergreen plants
(from Jerry Stowell's The Beginner's Guide to American Bonsai, 1986, 1978, Appendix C,
pp. 120-121)
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