Japanese Dwarf Garden Juniper - Juniperus procumbens
nana
General Information:
This is the 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).
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