Thuja: What You Need To Know | Hedging UK

Thuja (Thuja occidentalis), often called White Cedar or Arborvitae, is a popular evergreen conifer used widely for dense, formal hedging. Its richly green, aromatic foliage and excellent growth habit make it a reliable choice for those seeking year-round privacy, structure, and minimal maintenance.

Below is some useful information about using Thuja for hedges, or take a look at our Thuja Hedging Plants for sale.

Thuja Description:

Growth Habit:

Thuja forms a dense, upright evergreen hedge with a naturally conical habit if left untrimmed. It responds exceptionally well to shaping and creates a tidy, formal screen when regularly clipped.

Foliage:

The foliage is flattened, scale-like, and rich green throughout the year. It is often lightly aromatic when brushed or trimmed, releasing a fresh, cedar-like scent.

Flowers and Fruits:

Thuja produces small, inconspicuous cones, which are not messy and do not affect its ornamental value. Flowers are minimal and not showy.

Sunlight and Soil Requirements:

These hedges grow well in full sun to partial shade and are adaptable to a range of soil types, including clay, loam, and sandy soils. It prefers moist, well-drained ground but is tolerant of short periods of drought once established.

Hedge Pruning:

Prune in late spring or early summer, and again in late summer if needed. Avoid cutting into old wood— it doesn’t regenerate from hard cuts into brown stems.

Maintenance:

Thuja is low maintenance once established. Water deeply during prolonged dry spells in the first couple of years. Apply mulch annually to conserve moisture and feed with a balanced slow-release fertiliser in spring.

Hardiness:

This hedge species is fully hardy in the UK and performs well in exposed or sheltered positions. It tolerates wind and frost but may suffer slight browning in extremely harsh winters or coastal winds.

Toxicity:

Thuja foliage is mildly toxic if ingested and should not be consumed by pets or livestock. However, it is safe for use in gardens with pets as long as they don’t chew on the leaves.

Where is the Best Place to Plant a Thuja Hedge?

Light Requirements:
Full sun promotes dense, even growth. It will tolerate partial shade but may be slightly less vigorous.

Soil Type:
These hedges thrive in moist, fertile, well-drained soil. Avoid very dry or waterlogged ground.

Space and Size:
Best suited to boundary hedging where a tall, solid evergreen screen is needed.

Protection from Winds:
This species of hedge is wind-tolerant but benefits from some shelter in very exposed sites, especially when young.

Accessibility:
Ensure access for trimming at least once a year and room to reach the base of the hedge.

What Time of Year Do You Plant Thuja?

Plant in autumn (October–December) or spring (February–April) when the soil is warm and moist.

• Root balled or bare root plants: Best planted between November and March.

• Container-grown plants: Can be planted year-round with proper care and watering.

How Far Apart to Plant Thuja for a Hedge?

• Single row: 60–80cm apart

• For faster coverage, Space as close as 50cm apart

Spacing can be adjusted based on plant size at planting and desired density.

How Do I Plant Thuja?

• Dig a trench or individual holes twice the width of the rootball

• Improve poor soils with compost or well-rotted organic matter

• Set the plants at the same depth they were growing in the nursery

• Firm in well and water thoroughly after planting

• Apply a mulch layer and water regularly in dry weather

How Far to Plant Thuja from a Fence?

Allow at least 60 cm (2 feet) of space between the hedge and a fence or wall. This allows for air circulation, light access, and room to trim the back side.

How Fast Does Thuja Grow?

Thuja is a moderate to fast-growing plant, especially when young, adding 30–60 cm (1–2 feet) of growth per year under ideal conditions.

How Big Does Thuja Get?

Untrimmed, they can grow to 12–15 metres (40–50 feet) tall and 4–6 metres (13–20 feet) wide. When grown as a hedge, it is usually maintained at 2 to 5 metres (6–16 feet) high, depending on preference and purpose.

Is Thuja Hardy in the UK?

Yes—These hedges are fully hardy, thriving across most of the UK. It is cold-tolerant and wind-resistant, though very harsh coastal winds may cause minor leaf browning.

Can You Keep Thuja Small?

Yes. They can be maintained as a compact hedge as low as 1.5 metres with regular annual trimming. For best results, trim little and often rather than infrequent, heavy cuts.

Can Thuja Be Cut Back Hard?

Thuja does not regenerate well from old wood. Avoid cutting into brown or bare stems, as they may not resprout. Instead, shape the hedge regularly while the growth is still green.

How Do You Thicken a Thuja Hedge?

To increase density:

• Trim lightly every year to promote bushy growth

• Feed in early spring with a slow-release fertiliser

• Ensure adequate water and mulch during dry spells

• Keep the top of the hedge slightly narrower than the base to allow light to reach lower foliage

Which is Better: Thuja or Leylandii?

Both are excellent for tall, evergreen hedging:

• Thuja is slower-growing but easier to manage and shape

• Leylandii grows faster but needs more frequent pruning

• Thuja is often preferred for smaller gardens or where scent, formality, or ease of maintenance is valued

Do Thuja Hedges Stay Green All Year?

Yes—they are a true evergreen. They feature dense, green foliage year-round, making them ideal for providing privacy and reducing noise. Occasional minor browning in winter is normal, but it is not usually severe.

Conclusion

Thuja (Thuja occidentalis) is a refined, evergreen conifer offering structure, scent, and shelter all year round. Its manageable growth habit, resilience, and attractive foliage make it a fantastic choice for formal hedges, garden boundaries, and windbreaks. With regular care, these attractive hedges will reward you with decades of lush green privacy.