Plant Overview

Common juniper (Juniperus communis) is a versatile evergreen conifer native to the northern hemisphere. Known for its adaptability and hardiness, it has become a popular choice for landscaping and gardening.

Types and Varieties

While less common in cultivation than its counterpart, Chinese juniper, there are still a wide range of common juniper cultivars available. These include:

• Juniperis communis ‘Gold Cone’: Columnar form with light greenish leaves
• Juniperis communis ‘Repanda’: Prostrate groundcover form
• Juniperis communis ‘Compressa’: Upright, cone-shaped shrub
• Juniperis communis ‘Hibernica’: Pillar-shaped shrub
• Juniperis communis ‘Blue Stripe’: Prostrate form with blue-striped leaves

Planting and Care

Planting:

• Plant in well-draining soil with a pH between 4.0 and 8.0.
• Dig a hole twice as wide as the root ball and amend the soil with organic material.
• Position the shrub at the same height it was in its container.

Watering:

• Common junipers are drought-tolerant but prefer moist soil.
• Do not overwater, as they cannot withstand waterlogged conditions.

Sunlight:

• These sun-loving plants require full sun for optimal growth.

Temperature:

• Hardy in USDA zones 2 to 7, most common juniper varieties can withstand temperatures as low as -49 degrees Fahrenheit.

Fertilization:

• Common junipers are light feeders and do not require regular fertilization. A yearly application of a slow-release shrub and tree fertilizer in late winter or early spring may be beneficial.

Pruning:

• Pruning is generally not necessary, but can be done in late winter to remove diseased or broken branches.
• When pruning for shape, cut individual branches back to an upward-growing side branch.

Propagation

Rooting Cuttings:

• Take 4- to 6-inch cuttings from the tips of branches in late summer.
• Dip the cut ends in rooting hormone and plant in a porous potting medium.
• Keep the cuttings moist and in a sheltered location until roots develop (6-12 weeks).

Growing from Seed:

• Common junipers are dioecious, meaning they have male and female plants. Both must be present for cross-pollination and fruit production.
• Harvest ripe berries (turned purple/black) and sow the seeds directly into the garden or stratify them for up to 120 days before planting.
• Germination rates are poor, so sow several seeds at once.
• Seedlings will grow slowly and may take up to two years to reach a suitable size for transplanting.

Potting and Overwintering

Potting:

• Small upright varieties of common juniper can be grown in containers.
• Use a well-draining potting mix with added sand or perlite.

Overwintering:

• In colder climates, potted junipers may need to be moved indoors or covered with mulch for the winter.
• Avoid keeping them indoors for extended periods, as they require a cold dormant period.

Pests and Diseases

Common Pests:

• Bagworms
• Juniper scale
• Aphids

Common Diseases:

• Juniper blight
• Twig blight
• Cedar apple rust

Problem-Solving

Tips of Branches Dying:

• Check for fungal diseases (blight) and prune off affected branches.

Leaves Die Back Along One Side:

• Indicates winter burn from desiccation. If severe, the shrub may die.

Branches Die, One at a Time:

• Phytophthora root rot may be the cause. Prune away damaged branches and improve soil drainage.

Needles Turn Brown and Fall Off:

• May be caused by overwatering, underwatering, or pet urine.

Additional Uses and Considerations

Practical Uses:

• Juniper berries are used for flavoring gin, tea, and culinary dishes.
• The plant provides food and shelter for wildlife.

Comparison to Chinese Juniper:

• Common juniper has more needle-like leaves and bluish berries.
• It is better suited for colder climates than Chinese juniper.

Landscaping Applications:

• Common junipers are versatile shrubs for mass plantings, groundcovers, rock gardens, and general garden use.
• Different cultivars offer a range of forms and sizes to suit specific landscaping needs.

Edible Berries:

• Juniper berries are edible, but caution is advised as some juniper species have toxic berries.
• Berries take 2-3 years to ripen and may be scarce due to birds consuming them.