Eastern Red Cedar

  • Juniperus virginiana

    Juniperus virginiana

    Common Name:

    Eastern Red Cedar

    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 mould, 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. Die back 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 die back when Junipers are covered with ice for several days. Removing the ice is impractical.

    Junipers are a favourite 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).

    Bibliography:

    USDA Fact Sheet ST-327

    Compiled by Sabrina Caine

    Edited by Thomas L. Zane