Box blight (also known as boxwood leaf drop) was first found in the UK around 1990. Since then it has been found throughout Europe and as far away as New Zealand, Ohio, Oregon, Pennsylvania, New York and British Columbia to name a few places.  There are two types of organisms which can cause box blight and they can both occur at the same time. Volutella buxi which is the asexual stage of the fungus Pseudonectria rousseliana and the fungus Cylindrocladium buxicola that produces symptoms similar to Volutella.

Volutella buxi results in browning of the leaves leaving bare patches in topiary and hedges. It can spread in wet conditions with a  pinkish spore appearing on the undersides of leaves. Fallen leaves can carry the disease through the winter months and new spores are produced in the spring. They can enter the plant through damage to leaves, stems and clipping cuts.

Cylindrocladium buxicola is the more serious of the two and this causes leaves to develop dark brown spots which enlarge and patches of grayish fungal growth appear on the underside of the leaves which release the infection. This form of infection can penetrate the cuticle of the leaves meaning infection can occur and spread easily.

Special efforts to remove infected parts of the plant or debris are required to help reduce the spread of the infection, burning is best but do not add to the compost heap as spores have been found decomposing leaves up to a year after.


There is no know cure for box blight.  It may be possible to prevent the spread by using fungicides but these need to be applied to the whole plant including leaves and stems but this can be very difficult as box leaves are very tightly packed.

If you find an infected area hygiene is very important.  Any tools used to clip or prune should be disinfected after use.  Household bleach is suitable for this.

All infected branches and fallen material at the base of the plant are to be removed carefully as not to spread the spores and infection.  These are best to be burnt.

Never compost infected material.

Avoid over head watering as this can cause the spores to spread.

But remember not all browning of leaves means you have box blight.  Pruning to late into the season can lead to frost damage, the foliage on the top will be brown but you will get new growth underneath.  Also cat or dog urine can cause dead patches on the lower part of the plan.
Make sure you inspect the infected area first to asses the cause of the problem before taking drastic actions and cutting big patches from your hedges or topiary.