Eastern Red Cedar - Juniperus virginiana
General Information: Red cedar is an evergreen growing 40 to 50 feet tall in
an oval, columnar, or pyramidal form (very diverse) and
spreading 8 to 15 feet when given a sunny location. It
develops a brownish tint in winter in the north and is
sometimes used in windbreaks or screens. The fruit is a
blue berry on female trees and is ornamental when
produced in quantity. Birds devour the fruit and 'plant'
it along farm fences and in old abandoned fields. Some
botanists do not separate J. virginiana from silicicola.
The eastern red cedar is not a true cedar (genus Cedrus),
it is actually a variety of juniper. It occurs naturally
as an upright tree with many small branches, curving
sharply upward. Old trees often have many natural jin on
the lower part of the trunk, and that branches are more
nearly horizontal. The wood of the red cedar is fragrant
and is
used extensively for furniture. The foliage is bright
green to dark
green.
With sufficient early training, the red cedar can be
used for most styles, though multiple-trunk styles
probably require planting multiple trees close together.
Cascade and semi-cascade styles could be a challenge,
given the strong apex dominance of this tree.
Family: Cupressaceae
Lighting: Full sun or
part shade.
Temperature: Hardy in
zone 2 through 9.
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:
Reduce the roots gradually, removing no more than one
third of the roots at each repotting. 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
or layering.
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. For junipers, 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:
Pests: Bagworm caterpillars occasionally web foliage and
debris together to make bags up to two inches long. The
insects live in the bags and emerge to feed on the
foliage. Use sprays of Bacillus thuringiensis. The
insects can also be picked off the plants by hand.
Juniper scale causes yellowed needles, and infected
branches fail to produce new growth. The scale is round
and at first white, later turning gray or black. The
Juniper webworm webs twigs and needles together, causing
them to brown and die. The larva is 1/2-inch-long and is
brown with darker stripes. The larvae are often in the
densest part of the plant and can go unnoticed. Mites
cause
stippled and bronzed foliage.
Diseases: Twig blights
cause death and browning of twigs tips. The diseases may
progress down the stem killing the whole branch. Small
lesions may be seen at the base of dead tissue. Prune
out dead branch tips. Dieback from Kabatina blight
appears in early spring, from Phomopsis in summer. Three
rust diseases seen most often are
cedar-apple rust, hawthorn rust, and quince rust. The
most common is cedar-apple rust. On Juniper the first
two diseases form galls and orange jelly-like horns in
spring. The horns are most likely to form following
periods of rainy, warm weather. Spores formed in the
horns infect the alternate host. The diseases are more
serious on the
alternate host than Juniper. Prune out the spore horns
when seen in the spring. Do not plant near hawthorns,
apples, or crabapples. Junipers are not tolerant of ice
coatings. Expect dieback when Junipers are covered with
ice for several days. Removing the ice is
impractical. 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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