Oriental arborvitae (Platycladus orientalis)

Overview

The Platycladus orientalis, commonly known across gardens as Oriental arborvitae, offers structure and year-round deep green texture to the landscape. This needled evergreen is valued for its naturally dense, conical, or columnar habit, making it an excellent choice for formal plantings or privacy screens. While the species can reach significant heights, many popular cultivars remain manageable as large shrubs.

Native to East Asia, Platycladus orientalis adapts well to a range of conditions, performing best when situated in full sun, though it tolerates partial afternoon shade. Gardeners appreciate its scale-like, yellowish-green foliage that often develops attractive winter bronze tones, especially when exposed to harsh winter elements.

Functionally, the Oriental arborvitae provides superb screening potential due to its tight growth habit. Ensure proper air circulation and moderate moisture levels for a healthy specimen or hedge, as poor siting can sometimes lead to aesthetic issues or pest susceptibility.

Fast Facts

• Plant Family: Cupressaceae
• Plant Type: Needled evergreen
• Native Range: China, Korea, Russian Far East
• Hardiness Zones: USDA Zones 6-9
• Size at Maturity:
  • Height: 18-25 ft
  • Spread: 10-15 ft
• Bloom Time: Non-flowering
• Bloom Description: Non-flowering
• Sun Exposure: Full sun to part shade
• Water Needs: Medium
• Maintenance Level: Medium

How to Grow

The best time to plant Platycladus orientalis is in the spring or fall when temperatures are mild, allowing the root system to establish before summer heat or deep winter freezes stress the plant. This evergreen thrives in fertile, well-drained soils when provided with medium moisture. Full sun exposure encourages the densest growth, although Oriental arborvitae can handle some light afternoon shade.

Water plants regularly, especially during hot, dry summer periods, to maintain that medium moisture level essential for health. Avoid overly wet sites where drainage is poor, as this can lead to root issues. This species generally requires minimal fertilization unless grown in extremely poor soil. Pruning is usually limited to occasional tip trimming to maintain a formal shape, although shaping should be done sparingly as heavy shearing can damage the structure.

Gardeners in borderline hardiness areas, specifically those at the northern edge of USDA Zone 5, should exercise caution. Platycladus orientalis may not demonstrate reliable winter hardiness throughout those colder regions. Furthermore, site selections in areas prone to very strong winter winds should be avoided, as branches can be easily broken by heavy snow load or wind stress.

Landscape Uses

The primary ornamental roles for Platycladus orientalis center around structure, mass planting, and screening. Its inherently pyramidal or columnar form makes it an outstanding choice when utilized as a stately Specimen tree, anchoring a corner of the landscape or providing vertical contrast against lower plantings.

However, the species is perhaps most frequently employed as an excellent Hedge. When planted in rows and properly maintained, the dense growth of the Oriental arborvitae creates an effective, dense visual barrier or property line marker that remains evergreen throughout the year. Smaller cultivars are frequently used near Foundations to add height variation without overwhelming the architecture.

For design cohesion, pair Platycladus orientalis with deciduous shrubs that offer contrasting fall color, such as Japanese maples or smokebushes, to break up the consistent evergreen texture. Ensure adequate spacing is allowed for mature spread to prevent overcrowding, which can compromise air circulation.

Standout Features

Noteworthy Characteristics

Platycladus orientalis, commonly called oriental thuja or Oriental arborvitae, typically grows as a dense, conical to columnar tree to 18-25’ tall, often appearing as a large shrub when young. The scale-like foliage emerges yellowish-green in flattened sprays and darkens to a deeper green with maturity, often displaying attractive bronze coloration in winter. This distinctive tree produces small, oval cones (to 3/4” long) and features reddish-brown bark.

Potential Problems

Healthy, well-maintained plants sited in proper growing environments usually have few major problems, making the Platycladus orientalis a relatively robust choice. Gardeners should watch for occasional infestations of bagworms and spider mites, requiring targeted treatment if populations become severe. Scales, aphids, caterpillars, borers, and mealybugs may also appear on stressed specimens. A structural concern unique to heavier snow regions is that branches may be easily broken from accumulated snow weight in winter, necessitating structural thinning or snow removal.

Tolerances

• Tolerates some light afternoon shade

Frequently Asked Questions

What hardiness zones is Oriental arborvitae suitable for?

The Oriental arborvitae (Platycladus orientalis) is reliably hardy in USDA Zones 6 through 9.

How large does Oriental arborvitae grow?

This tree typically matures to a height between 18 to 25 feet tall, with a spread generally ranging from 10 to 15 feet wide.

What sun exposure does Oriental arborvitae need?

For best performance, Platycladus orientalis requires full sun exposure, though it can tolerate locations that receive part shade.

When does Oriental arborvitae bloom?

This plant is classified as non-flowering; it produces cones instead of typical blooms.

Conclusion

The Platycladus orientalis offers a fantastic blend of reliable evergreen structure and manageable size, making it indispensable for screening and specimen planting in temperate gardens. Whether utilized in a formal hedge or as a foundational accent, this Oriental arborvitae delivers year-round visual interest. Before planting, confirm your landscape falls within USDA Zones 6-9 and plan for its medium water needs during establishment.

Companion Planting

When selecting companions for Platycladus orientalis, focus on plants that share similar cultural needs regarding sun and drainage. Low-growing, broadleaf evergreens like Japanese Holly (Ilex crenata) or dwarf rhododendrons create a nice foundational layer beneath the taller, columnar form of the Oriental arborvitae. Plants with contrasting leaf textures, such as ferns or ornamental grasses, placed nearby will highlight the fine texture of the Platycladus orientalis foliage. Avoid planting moisture-loving perennials directly beneath the canopy, as the established evergreen will absorb substantial water resources.

Design Ideas for Vertical Interest

The upright habit of the Platycladus orientalis is perfect for adding necessary vertical punctuation in mixed borders or foundation plantings. Where space is limited, selecting compact cultivars of Platycladus orientalis allows one to echo the columnar form in smaller garden beds without the commitment of the full species size. Use these trees as informal sentinels flanking an entryway or gateway, providing a strong sense of arrival. In contemporary designs, mass planting several specimens in a staggered line creates a dramatic, textured screen superior to standard sightline barriers.