Garden Pest Management: Safeguarding Your Buxus Sempervirens


Buxus Sempervirens – Garden Pest Management and Box Blight Treatment Guide.

Commonly known as box plants, Buxus Sempervirens has been a staple in gardens. This plant has been the backbone of many designed gardens for hundreds of years. Buxus allows for the creation of amazing and wonderful shapes through careful clipping. You might have seen Buxus in various National Trust properties, shaping borders and intricate designs like Parterres.

Historical Significance of Buxus Sempervirens in Garden Design


Esteemed for its dense foliage and precision in form, Buxus Sempervirens carries a rich heritage in garden design. Buxus thrives in both old and modern gardens, showcasing its enduring appeal and versatility. It highlights the plant’s cultural importance over time.

However, in recent years there has been much discussion, as to the continued use of Buxus in design. This is because of 2 main problems that the plant is experiencing: Box Blight and Box Tree Moth/caterpillars and their life-cycle.

Understanding Box Blight and Box Tree Moth

In the realm of garden pest management, Box Blight and the Box Tree Moth have emerged as significant threats. Early detection, understanding the symptoms, and applying the right treatment methods are essential steps in managing these issues effectively.

In garden pest control, Box Blight is a major issue, damaging the leaves and stems of Buxus Sempervirens. Symptoms in affected plants include bare patches where defoliation has occurred, indicating it’s time to treat box blight. Darker lesions on the leaves, white spores on the undersides of infected leaves and black streaks and die back on young stems. It doesn’t affect the roots.
Early detection is key in Box Blight treatment, though successful eradication can be challenging. The problem is that we are experiencing milder, wetter winters and the fungal spores thrive in these conditions.

So how do you help your plants to thrive?

Prioritising healthy plants and implementing strategies to prevent box blight can safeguard your garden’s vitality. Work on a dry day, as this will help to reduce the risk of fungal spores spreading. They love damp, humid conditions. Good garden hygiene and sterilising pruning tools are crucial steps in managing pests and diseases.

You will need clean, sharp tools to work with and disinfect them regularly between plants. To be safe, remove up to half or a third of the infected parts and a little bit more around those areas.
Don’t use power tools to remove infected parts of the plant, as they cause more damage by crushing and tearing the stem ends. Clear away all the debris to minimise re-infection. Current horticultural recommendations are that you should limit pruning to once a year.

Young plants benefit from careful pruning in May, reducing the chance of disease and promoting lush growth. Older, established plants are better cut in August, when growth has slowed down. This minimises the risk of damage to the leaves, either by weather conditions or disease.

Adding effective pest control methods to your gardening routine is crucial for keeping your garden healthy and beautiful. Adding effective pest control methods to your gardening routine is key to keeping your garden healthy and looking good. Check plants regularly for pests, use traps, and treat at the right time for good pest control.

When planting box in your garden, choosing disease-resistant varieties can significantly enhance garden aesthetics and health. Buxus microphylla ‘Faulkner’ & ‘John Baldwin’ are proving worthy contenders.

Using fungicides helps control diseases, so quarantining new plants for 4 weeks protects your existing Buxus. Don’t forget to water them and inspect them periodically during this time for any of the above signs. If everything appears to be fine after this time, plant out and enjoy.

The Second problem to look out for

Controlling garden pest problems, especially Box tree moth and their caterpillars, is essential for garden health. The Box Tree Moth, from East Asia, likely reached the UK on imported plants around 2007. The caterpillars cause most of their damage between March and October and can kill a plant in a matter of weeks.

The symptoms to look out for are similar to Box blight. Seeing leaves fall, bare spots, or webs on leaves are early signs of Box Tree caterpillar problems. They are about 4cm long, have black heads and greenish, yellow with black and white lines along their bodies. The adult moths have iridescent white wings with drown margins and lay their flat pale yellow eggs on the underside of buxus leaves.



Organic & cultural methods of control are preferable. If you only have a few plants, the best way is to carefully pick off the offending caterpillars and destroy them. Protect your health and the environment by avoiding pesticides.

They will kill non-target species, reduce biodiversity, damage soils, and have adverse effects on the wider environment. Think of pheromone traps as an early alert for spotting male moths.
They may reduce the population, but they will not eradicate the problem. They indicate the arrival of moths, the egg-laying stage, and subsequent caterpillar development. Traps are most effective when used between April and September. Hang the trap about 2m above the ground, near the Buxus shrub or hedge.

Fight Box Blight and caterpillars naturally with biological controls like bacteria and nematodes. The most common of these are Bacillus thuringiensis bacterium and the nematode Steinernema carpocapsae. Dilute biological controls with water and spray directly onto caterpillars. Apply in the evening or on a cloudy day for best results.

Many gardeners have simply given up trying to save Buxus. It can become an expensive and time-consuming exercise. Alternatively, replace Buxus with a different plant altogether. Good examples would be Euonymus, Ilex crenata (Japanese Holly), Ligustrum ovalifolium (Privet), Lonicera nitida (shrubby Honeysuckle), Osmanthus, Phillyrea, or Taxus baccata (Yew).



How often should I inspect my Buxus for signs of pests and diseases?

Regular inspections are crucial for early detection and effective management. Check your Buxus plants at least once a month, increasing to weekly during the peak growing season (spring through fall).

Can Box Blight and Box Tree Moth be completely eradicated from my garden?

While complete eradication can be challenging, consistent and targeted treatments can significantly reduce their presence and damage. Employing both cultural and biological control methods enhances your success rate.

Are there any completely resistant Buxus varieties to Box Blight and Box Tree Moth?

While no variety is completely resistant, some, like Buxus microphylla ‘Faulkner’ and ‘John Baldwin’, show greater resilience. Research and consult with local nurseries for the most up-to-date information on resistant varieties.

What are the best alternatives to Buxus that offer a similar aesthetic?

For a low-maintenance alternative to Boxwood, try Euonymus, Japanese Holly, or Yew. They offer a similar aesthetic with less upkeep.

Is it safe to plant new Buxus in an area where infected plants were previously removed?

Yes, but it’s advisable to replace the soil or treat it to reduce the risk of reinfection. Waiting a season before replanting can also help ensure that the area is clear of pathogens.

How can I dispose of infected Buxus material safely?

Remove infected plant material from your garden and dispose of it responsibly. Do not compost it, as this can spread the disease. Check with your local waste management services for guidelines on disposing of garden waste.

Can natural predators be used to control Box Tree Moths effectively?

While natural predators can help, they are often not enough to control large infestations. A combined approach using natural predators, pheromone traps, and biological treatments provides the most effective Box Tree Moth management.

How can I contribute to preventing the spread of Box Blight and Box Tree Moth in my community?

Educate yourself and others about the importance of early detection, proper treatment, and responsible gardening practices. Sharing information and strategies with fellow gardeners can help raise awareness and prevent the spread of these issues.