Type to search

Box Blight: How to Manage Fungal Outbreaks


Many gardeners dread the idea of box blight affecting their box hedging. Hedging can have a long life, but when the fungal disease known as box blight comes along, that life is cut short. This article will give you the best information regarding how to remove box blight, what to do when a fungal outbreak occurs, and the earliest signs and symptoms that you can look out for before it begins infecting your box hedging.

We will explore the following in this article:

What is Box Blight?

In case you are new to gardening, box blight is a common fungal outbreak that infects box hedging. It is a more severe fungus than Volutella blight. Although Volutella is less serious than box blight, they both still affect the plant in unpleasant ways. Box blight looks like an unnatural yellow colour forming on the hedging, appearing almost sickly, and gradually spreads across its green leaves.

How to identify Box Blight

Several strategies can be made to counter box blight from occurring. However, before you begin creating your strategy, you need to be aware of the symptoms of box blight.

Fortunately, box blight will not kill the roots of box plants if you decide to clip them. However, there is a high risk of new box hedging becoming infected by the fungus too.

Symptoms of box blight include:

  • Brown leaves that have fallen and will leave patches on hedging.
  • Black streaks on young stems.
  • White spores can be seen around the fungus and infected leaves in damp or wet conditions. If you are unsure, place the leaves in a plastic bag with a moist tissue.

Review garden hygiene and check for infection

  1. Upon identifying that your box hedging has contracted box blight, you should begin disposing of the infected or rotten material to prevent debris from building up in your garden. Since the material is infected, using it for compost is pointless since there will be no nutritional value.
  2. Ensure you regulate cleaning your pruning tools because otherwise, when you go to reuse them, it could lead to other plant life contracting an infection too.
  3. Check the soles of your shoes to see if they have come into contact with the soil or leaves. Clean them to remove any lingering spores.
  4. Begin applying fungicide once you have cut back the infected plants. This will help reduce spores developing and spreading during the cutting process.
  5. Ensure new plants are quarantined to prevent box blight from spreading to them.

Box Blight Treatment: How to control pests and diseases

Because box fungi thrives on infected leaves or stems, it would be best if you got rid of these as soon as possible to prevent further contamination on uninfected leaves. Box blight also likes wet conditions, so if you want to begin cutting back, you are best off doing this when weather conditions are dry.

Controlling pests and diseases: There are simple, effective ways to practically encourage and control protection of box hedging. Improving your garden hygiene and cultivation methods are a good place to start, as well as monitoring pests that may pose a threat. If you use any form of chemical control, it should be kept to a minimum to prevent affecting plant life too.

Control without chemicals: This is a more efficient way to control the risk of box infection. Taking cuttings from already healthy box in your garden will help reduce the chance of infection. You should also regularly monitor early signs of box when the weather is warm, as this will cause box blight to be more difficult to manage.

Furthermore, you should reduce clipping box regularly to allow for more ventilation. Avoid watering box from overhead, as this gives box blight the humid conditions it needs to survive. Instead, use mulch under the plants, which will reduce rain splashes. Regulate plant feeding too.

Add amazing garden accessories to your garden now.

box blight fungal outbreak on box hedging

Cutting back or cutting out hedging

Cutting back or cutting out the infection entirely will help reduce the chance of the plant being destroyed and likely a healthy recovery. However, you need to prioritise which sections of box you wish to plant and safeguard.

Identifying diseased plants: Any areas of the box hedging that have turned brown or fallen may well have been infected, especially if there are black streaks or no green colouring left under the bark.

Removing infections: do not touch the healthy box hedging after already coming into contact with the infected ones. Even cutting more than is necessary will help in case infections are less visible.

Reducing the box height by half will prevent an infection from spreading across larger areas. Check that no black streaks are left after you have cut back.

Ensure you clean all pruning tools after use.

Cutting stumps: this process is most useful when the infection is more severe, and you do not want to use fungicides since they could also be harmful to the plant. In addition, cutting the stump will increase the chance of removing all infected tissue and inoculum.

Infested soil and leaves: Before you begin clipping, lay down a tarpaulin which will help collect any clippings or debris that you remove, and dislodged leaves. Make sure to remove all fallen leaves around the hedging. After removing the leaves, remove a layer of soil from under the plants to get rid of any leaf remains, and then you can add a new layer of fresh soil with mulch.

Effective Fungicides Against Box Blight

Lastly, we need to consider whether using fungicides when managing a fungal outbreak for box blight. Most fungicides will not likely control box blight in itself; therefore, you need to implement additional methods in order to prevent it from spreading across the whole hedging.

The best forms of fungicide you can consider is Fungus Clear Ultra (Triticonazole) which is largely used for diseases that grow on garden ornaments. For relevancy, this is the most legal control method you could use on the box blight following relevant label instructions. Also, do not spray when rain is forecast, as this will also impact the growth of box blight otherwise.

Check out the Government’s advice for complaints about garden hedging here.

How to Avoid Box Blight

The first thing you should do in order to avoid box blight is to not plant box hedging! Even if you have recently moved to a new property, and there is already box hedging planted in your garden, be swift to remove the hedging and plant a new form of hedging to prevent infection. We have plenty of information and guidance towards the best hedge varieties in the UK.

Varieties of box hedging that are more resistant to box blight includes B. microphylla and ‘Faulkner,’ both which are known to be less susceptible to box blight than other Buxus subspecies.

Additionally, you need to ensure that you quarantine your new box hedging plants for four weeks so that they do not get infected. Apply your quarantine methods before planting in your garden. Even if you have had visitors in your garden recently, make sure that they maintain as little contact to the box as possible. Place box topiary where it will not easily get brushed by or handled by people. You can also improve your garden ideas and pathways so that they are wider and will not come into contact with living organisms as often, to help improve its air circulation.

Remove Box Blight from Your Garden Today

Like many diseases, box blight loves to thrive in warm, moist conditions, and since Britain is a mostly cold country, you will most likely encounter the disease in spring and summer. If, however, it does appear in rainy periods throughout the year, you should be more cautious of controlling box since it can also affect the hedging if the correct measures are not made. As you may have seen from this article, there are several ways to tackle box blight, but it will need to be handled carefully so as to not escalate the risk of infection for the rest of the plant.


What is box blight?

Box blight is a fungus that can infect boxwood plants. Common symptoms include leaf spotting, leaf drop, and twig blight. These can cause the infected plant to eventually die if untreated.

What are the symptoms of box blight?

Symptoms of box blight may include
– Brown spots on the leaves.
– Black streaks on leaf stems.
– Twig blight.
– Irregular leaf drop.

If your box hedging is showing any of these symptoms, then follow the instructions laid out in this article.

How does box blight spread?

Box blight can be spread by weather conditions, especially the wind and rain, and if pruning tools have not been properly cleaned after coming into contact with the infected plants.

How can I treat box blight?

Whilst there is not a cure for box blight, there are ways you can manage the disease. This may include pruning infected branches (and sterilising the equipment used after), applying appropriate fungicides, improving the air circulation, and destroying any infected debris.

Can box blight be removed from soil?

Box blight cannot be removed from soil. However, if your soil has become infected with box blight, you can replace the soil with fresh soil instead, before you add new boxwood plants to your garden.


Hedges Direct. (n.d.). Box Faulkner. [Accessed 3rd May, 2023] Retrieved from: https://www.hedging.co.uk/box-faulkner

UK Government. (n.d.). Over the Garden Hedge. [Accessed 1st March, 2023] Retrieved from: https://www.gov.uk/government/publications/over-the-garden-hedge

David Austin Roses. (n.d.). Fungus Clear Ultra. [Accessed 26/05/23] Retrieved from: https://www.davidaustinroses.co.uk/products/fungus-clear-ultra

Anna Sharples

Anna is the marketing and office manager for Garden Benches - a premium supplier of high-quality wooden benches and other outdoor furniture.

  • 1

Leave a Comment

Your email address will not be published. Required fields are marked *