Dwarf
Japanese Juniper
is a tree that is most often used for the ubiquitous "mall
bonsai". In spite of this bad press, it does in fact make
a fine bonsai if it is properly trained and cared for (unlike
the average "mall bonsai").
This
juniper has a low, spreading habit that makes it ideal for cascade
and semi-cascade styles. Specimens grown in a nursery or specifically
for bonsai can be used for many styles, but probably not for
formal upright. In nature it grows as a small ground-cover shrub.
The foliage is bright green.
Lighting:
Full sun.
Temperature:
Tolerates a wide range of temperatures, including freezing,
however, roots must be protcted from excessive heat or cold.
Watering:
Spray the foliage with water daily during the
growing season. Water when the soil is moderately dry (to a
depth of 1/2 to 1 inch) but do not let the soil dry out completely.
Feeding:
Simon and Schuster's recommends feeding junipers from early
spring to autumn ever 20-30 days using a slow-acting organic
fertilizer. If you prefer to use chemical fertilizers, apply
a half-strength solution every other week of a reasonably balanced
fertilizer, such as Peter's 20-20-20. You may wish to alternate
with an acidic fertilizer such as Miracid. You should not fertilize
during the hottest part of the summer (July-mid August in the
northern hemisphere), or if the tree is weak or has recently
(2-4 weeks) been repotted.
Pruning
and wiring: To develop the foliage, pinch out the tender new
shoots using your fingers. Do not use scissors, as the cut needles
will turn brown. Pinching must be done continuously during the
growing season. Prune undesirable branches (especially those
growing straight down from their parent branch) when repotting
or during the growing season.
Wiring
is best done in autumn or early winter, so that the branches
can become accustomed to their new position while the tree is
dormant. Wiring done at other times must be watched carefully
for signs of wire cutting into the bark, and must be removed
immediately if this happens. If necessary, the tree can be re-wired
after removing the old wire.
Propagation:
Cuttings rooted under mist, layering.
Repotting
Reduce the roots gradually, removing no more than one third
of the roots at each repotting. Repot young trees (up to 10
years) every other year. Repot older trees every 3-4 years.
Repotting is best done in spring. Junipers can also be repotted
in autumn if necessary, since they enter a period of renewed
root growth at that time. Extensive root pruning in autumn is
probably not a good idea, however.
Simon
and Schuster's recommends 60% soil, 10% peat, and 30% coarse
sand. Rémy Samson recommends 1 part loam, 1 part leaf
mold, and 1 part coarse sand. Peter Chan recommends 1 part loam,
1 part peat, and 3 parts coarse sand.
The
tree should be protected from wind and direct sun for a month
or two after repotting.
Pests
and diseases: Junipers are a favorite victim of red spider mites.
If the tree appears weak, with yellowing foliage, it may have
spider mites. To check for spider mites, hold a sheet of white
paper under a branch and gently shake the foliage. If the paper
comes away with many small dots that move, it has spider mites.
To combat spider mites, spray with insecticidal soap or a nicotine
solution (which can be made by soaking tobacco in water overnight).
