Thuja orientalis (Oriental Arborvitae)

Thuja orientalis, commonly known as Oriental Arborvitae, is a diverse and adaptable evergreen, suitable for a range of landscape applications, from creating privacy screens to serving as ornamental focal points in gardens.

Thuja orientalis: An In-depth Look

Native: Oriental Arborvitae is native to eastern Asia, particularly China and Korea.

Plant Type and Habit: Oriental Arborvitae is an evergreen conifer with a typical pyramidal growth habit. It is known for its dense and compact foliage, making it a popular choice for ornamental planting.

Size: The species can reach up to 18-25 feet tall (5.4 to 7.5 meters) and 10-15 feet wide (3 to 4.5 meters). In cultivation, you’ll find compact shrubby cultivars far more frequently than the species itself.

Cones: The cones are small, with a size typically around 1/2 inch to 3/4 inch long. They are initially green, turning to a brownish hue as they mature. Cones generally mature in the fall, about 6-8 months after pollination.

Foliage: The foliage consists of small, overlapping scales, creating a dense, textured appearance. The color varies from yellowish-green in youth, becoming darker green with age. Foliage may bronze up in winter.

Bark: The bark is fibrous and reddish-brown, becoming more textured and rugged with age.

Uses: Oriental Arborvitae is used for hedges, privacy screens, windbreaks, and as a decorative landscape plant. Dwarf varieties are popular in rock gardens and as specimen plants.

Hardiness: Hardy in USDA zones 6-9, it can adapt to a range of environmental conditions but prefers milder climates.

Wildlife: Provides limited shelter for small wildlife.

Toxicity: Generally considered non-toxic to humans and animals.

Deer and Rabbit: May experience some browsing from deer and rabbits.

Invasiveness: Not considered invasive; typically stays within its planted area.

Benefits: Offers evergreen foliage for year-round interest, low maintenance once established, and adaptability to a range of soil types and conditions.

Oriental Arborvitae Growing Tips

Light: Thrives in full sun but can grow well in light shade. Full sun exposure leads to denser foliage growth. Usually, it appreciates some light afternoon shade in hot summer climates.

Soil: Prefers well-drained, moist soil. It tolerates a variety of soil types, including clay, but does best in slightly acidic to neutral soil.

Water: Regular watering is important, especially in dry conditions and for newly planted trees.

Fertilizer: Apply a balanced, slow-release fertilizer in early spring. Avoid over-fertilizing, which can harm the plant.

Pruning: Little to no pruning is required. Prune for shaping or size control in late winter or early spring before new growth starts. Avoid heavy pruning into old wood.

Mulch: Provide a generous root zone mulch.

Propagation: Commonly propagated by semi-hardwood cuttings in summer.

Pests and Diseases: Watch for bagworms and spider mites. Aphids, mealybugs, scale insects, caterpillars, and borers may occur. Fungal diseases like root rot can occur in poorly drained soils. Good air circulation and proper planting depth help prevent these issues.