Boxwood blight is a disease that can quickly ruin a gorgeous landscape. It is a fungal disease spreading quickly across North America. The disease causes black spots to form on leaves, along with elongated black lesions on twigs and stems. Rapid defoliation (in a matter of weeks) soon follows the initial symptoms of infection.
Boxwood blight is often introduced into landscapes on infested nursery stock. Spores of pathogen can easily stick to shoes, clothing, and shearing/pruning tools, so the disease can be easily introduced during routine maintenance. New outbreaks commonly occur following shearing plants in summer.
Moisture on leaves and twigs provides ideal conditions for infection by this fungus so years with high rainfall and extended summer temperatures result in greater disease incidence and severity.
Here are some tips to consider…