An Unwelcome Visitor in Aylsham's Gardens

When we think about visitors to Aylsham, we usually think of people coming to enjoy our historic market town, beautiful countryside and well-tended gardens. But over recent years another visitor has arrived – one that nobody invited.

Across Aylsham and our surrounding villages, gardeners have watched in disbelief as carefully clipped hedges, formal borders and treasured topiary have been stripped almost overnight. The culprit is the Box Tree Caterpillar, the larval stage of the Box Tree Moth (Cydalima perspectalis), an invasive species that has spread rapidly across the United Kingdom.

For many gardeners, the damage feels particularly personal. Box (Buxus) has been a feature of British gardens for centuries, providing year-round structure and form. In some gardens it has taken decades to create the perfect hedge, spiral, ball or cloud-pruned shape. Seeing those living sculptures reduced to brown skeletons in a matter of weeks can be heartbreaking.

From East Asia to East Anglia

The Box Tree Moth is native to East Asia and is believed to have arrived in Europe through the international plant trade. It was first detected in Britain in 2007 and quickly established itself in southern England before spreading across the country. Today it is found throughout much of England, including Norfolk, and has become one of the most significant threats to box plants.

The caterpillars are voracious feeders. They consume leaves, spin silk webbing through plants and, in severe infestations, can even strip bark from stems. Left unchecked, they can completely defoliate a plant and cause extensive dieback.

Aylsham's Topiary Inspiration

The photographs accompanying this article demonstrate two very different realities.

Firstly, at the end of this post, we are delighted to feature images from local gardening expert and recent BBC-featured Topiarist of the Year winner, whose remarkable creations showcase exactly what can be achieved with patience, skill and healthy box plants. These stunning examples remind us why box remains such a beloved feature of traditional British gardens.

Alongside these images, we also show the devastating effect that Box Tree Caterpillars can have when an infestation takes hold. The contrast is striking: one image represents years of careful cultivation, the other just a few weeks of unchecked feeding.

Yet importantly, the story does not have to end with removal.

Don't Reach for the Spade Just Yet

Many gardeners assume that once a box plant has been attacked it is beyond saving. In reality, even heavily damaged plants can often recover if action is taken quickly.

The Royal Horticultural Society advises that gardeners inspect box plants regularly throughout the growing season. The caterpillars are active from spring through autumn and there can be multiple generations each year, meaning that one successful treatment is rarely enough.

Look out for:

• Fine silk webbing within the plant

• Green caterpillars with black stripes

• Leaves that appear skeletonised or eaten away

• Small green droppings beneath the plant

• Areas of sudden browning or defoliation

Early detection is often the difference between a minor setback and a major loss.

Winning the Battle Requires Vigilance

Unfortunately there is no permanent cure. Gardeners who wish to keep their box plants must be prepared for an ongoing management programme.

The RHS recommends regular inspections from early spring onwards, hand removal of caterpillars where practical, and monitoring for moth activity throughout the season. Pheromone traps can help indicate when adult moths are present in the area and when new generations may be emerging.

Many Norfolk gardeners report success using biological controls and targeted treatments, but they also emphasise that applications need to be repeated during the season. Local gardening discussions frequently highlight that persistence, rather than a single treatment, is what keeps treasured hedges and topiary alive year after year.

The key message is simple: monitor, inspect and act early.

A New Reality for Gardeners

There is no doubt that the Box Tree Caterpillar has changed gardening across Norfolk. Walk through many towns and villages and you will see damaged hedges or gaps where box plants once stood. Some gardeners have chosen to replace their plants entirely, while others have committed to protecting specimens that may have taken decades to establish.

Both approaches are understandable.

However, the magnificent examples of topiary featured alongside this article demonstrate why many gardeners are determined to persevere. Beautiful box specimens remain achievable, but they now require a level of attention that previous generations never had to consider.

The Takeaway

The arrival of the Box Tree Caterpillar may be one of Aylsham's least welcome visitors, but it does not necessarily signal the end for box in our gardens.

If you have box hedges or topiary, inspect them regularly, learn the warning signs, and be prepared to treat infestations promptly. With vigilance and persistence, many plants can recover and continue providing the structure, character and beauty that have made box such a cherished feature of British gardens for centuries.

The battle may be ongoing, but for many gardeners, it is still a battle worth fighting.

See the Real Thing for Yourself

If the photographs featured in this article have inspired you, there is an opportunity to see Paul's remarkable topiary and box gardens in person.

Paul and Sian Everden's beautiful garden at Hoste Barn, known through the National Garden Scheme as Old Manor Farmhouse, opens regularly to visitors in support of nursing and health charities. The garden has been developed over more than three decades around a restored seventeenth-century Dutch-gabled farmhouse and features extensive box knot gardens, topiary, pleached hornbeam avenues, formal hedging and a series of interconnected garden rooms. The property was shortlisted for the National Garden Scheme's Favourite Garden award and is widely regarded as one of Norfolk's most impressive private gardens.

A visit provides a wonderful reminder of what can be achieved with imagination, patience and careful maintenance. At a time when many gardeners are questioning whether box still has a place in British gardens, Hoste Barn demonstrates that these plants can continue to form the backbone of stunning garden design. The challenge posed by the Box Tree Caterpillar is real, but so too is the potential for creating beautiful and enduring topiary.