Hardy bonsai include all varieties that naturally occur in
temperate regions of the world. Therefore, these trees require
four distinct seasons including a cold winter dormancy. Hardy
bonsai include Juniper, Pine, Larch, Maple, Hornbeam and others.
These are generally not suited for growing indoors.
WATERING
Proper watering is critical! Feel the surface of the soil
daily. If the surface is dry or only slightly moist it is time to
water. Water from above and thoroughly soak the soil.
Watering the foliage as well as the soil is also beneficial for your
tree. Allow excess water to drain away quickly and never let your
tree sit in water for extended periods. During hot dry weather or
under windy conditions your tree will need frequent watering.
Very small bonsai in small pots can sometimes dry out in a day or
less. Most do not like their soil to become really dry.
Consistent bone-dry conditions are likely to kill your tree.
LIGHT
Conifers such as junipers, pines and spruces thrive in direct sunlight
and can gradually be acclimated to full sun. Deciduous trees such
as maples and elms need to be grown in very bright light to part
sun. Hot sun and wind can cause leaf burn, so you may need to
provide some protection from hot midday sun. Very small bonsai in
small pots do better in some shade.
TEMPERATURE
Hardy bonsai need a cold winter dormancy to grow well. Once
temperatures are consistently above freezing in spring, your bonsai
should be placed outside and allowed to remain there all spring,
summer, and fall. Once night temperatures drop below 35 degrees
your tree will need some winter protection from the cold and
wind. An unheated garage, basement, cold frame or a very, very
cool room in the house are all suitable locations. Bonsai that drop
their leaves can be placed in the dark. Even though dormant trees
use much less water, completely drying out can still be dangerous so
remember to check regularly for water.
FERTILIZING
Hardy bonsai do best with frequent feeding during the growing season
(spring, summer and fall). Organic feeding can be done with Green
King pellets. Miracle-gro or Schultz water soluble fertilizers
can be used but should be mixed only half as strong as the directions
recommend. The idea is to keep your tree healthy and maintain
very moderate growth. Do not feed in the winter.
REPOTTING AND STYLING
Most bonsai need to be repotted and/or root pruned every 2 to 3
years. It is best done in the spring once your tree has started
growing well again. Normally a quarter to half of the root mass
is removed to allow for fresh soil and new roots to grow which will
reinvigorate your tree. Occasional trimming and wiring will also
be necessary to maintain form. A good book or bonsai professional
might be a good consultant.
