Lately we have been seeing quite a bit of Boxwood Blight on the properties we visit. Boxwood blight is caused by a fungal pathogen and results in severe defoliation and die-back. The one most unique identifier of Boxwood Blight is that it does not seem to affect the roots.
All species of Boxwood are susceptible. The pathogen spreads through the air. The spores are activated by water and are most ineffective in humid or wet weather. The pathogen can survive in fallen leaves and in the soil for up to 5 years contributing to a long lived and wide spreading disease.
Unfortunately, it happens all too often that the symptoms appear too late in the season to provide treatment. Regularly scheduled fungicide applications are required to control Boxwood Blight. These applications should be provided in the Spring. If you see symptoms in your boxwood now, you should have an expert confirm the problem and be placed on a list for spring Fungicide treatments.
Image via ornamentalpathology.com