How to Thicken a Thuja Hedge

Tips for making your thuja hedge denser

August 08, 2025 | 8 min read
A dense and well-maintained Thuja hedge in a garden.

Known for their vibrant green foliage and robust growth, Thuja hedges are a popular choice across the UK. However, like any hedge, they can sometimes appear sparse if not properly cared for. Today, I'll share some practical steps to help you thicken your Thuja hedge.

Quick Answer

To thicken a Thuja hedge, prune regularly, feed with the right nutrients, and ensure proper watering. These steps encourage dense growth.

Understanding Thuja Hedges

Thuja, commonly known as arborvitae, are evergreen conifers that thrive in the UK climate. They're appreciated for their dense foliage and ability to form a solid barrier when grown as a hedge. However, without regular maintenance, they can become leggy.

Pruning Techniques

When to Prune

In the Midlands, it's best to prune your Thuja hedge in early spring or late summer. Avoid pruning in late autumn or winter to prevent frost damage.

How to Prune

Use sharp shears to trim back overgrown branches. Focus on cutting just above a node to encourage new shoots. Regular pruning helps maintain shape and encourages thicker growth.

Feeding Your Thuja

Proper nutrition is crucial for a dense hedge. Apply a balanced fertiliser in early spring, ensuring it contains nitrogen, phosphorus, and potassium. This will promote healthy foliage and root development.

Watering Wisely

Young Thuja hedges need regular watering, especially during dry spells common in the Midlands. Water deeply once a week, ensuring the soil is moist but not waterlogged. Mature hedges are more drought-tolerant but still benefit from occasional watering during prolonged dry periods.

Additional Tips for a Denser Hedge

  • Mulch around the base to conserve moisture and suppress weeds.
  • Space your plants about 60 cm apart for optimal growth.
  • Regularly inspect for pests and treat promptly to avoid damage.

Seasonal Care Calendar

Month Task Notes
March-April Prune and Fertilise First major prune of the year
July-August Prune Light shaping and maintenance
September Water Ensure adequate moisture for winter

Frequently Asked Questions

How often should I fertilise my Thuja hedge?

Fertilise once in early spring and again in mid-summer for best results.

Can I prune my Thuja hedge in the winter?

It's best to avoid winter pruning to prevent frost damage to the new growth.

What should I do if my Thuja hedge is turning brown?

Check for signs of pests or disease, ensure proper watering, and apply a suitable fertiliser to encourage recovery.

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