Boxwood Blight is Here, and It’s Not Going Away
In 2018 boxwood blight became a serious issue for many neighborhoods in Albemarle County and our surrounding areas. This included large plantings in the Farmington/Ednam neighborhoods as well as the Rugby Road area. Since then, our Horticultural Help Desk has been contacted to identify boxwood blight all over our beautiful community. Many of our plantings have historical significance given their age and location. Plants that can live for decades, even centuries, now stand at risk of destruction from the blight pathogen and will continue to face this threat for many years to come.
Symptoms of boxwood blight often go unnoticed before its too late. The fungal disease causes rapid defoliation, almost overnight when the environment is favorable. Seasons of extremely wet conditions, high humidity, and warmer temperature ranges are ideal for fungal spore generation. Welcome to Virginia, where our hot and humid summers come with many thunderstorms and heavy rainfall through August and September. This is the perfect climate for any number of fungal diseases to thrive in, especially the boxwood blight fungus.
Symptoms seen on your boxwoods are very specific to this disease. Most fungal pathogens will cause leaf spots, and this one does as well. However, black streaking on the stems and sudden, severe defoliation are only associated with the boxwood blight fungus.
Through late summer and into the fall, our Horticultural Help Desk has seen a resurgence of cases in our area. This is due to the capability of the fungal spores to live dormant in soil for many years, and then spring to life when conditions are right. All the diseased plant material, especially the leaf litter, that is left on the ground will also hold more sources of spores for the next growing season.
There is no cure for fungal diseases. According to the VCE Boxwood Blight Task Force, your best weapon against recurring blight is to select resistant cultivars, do a thorough cleanup when infected plant material is found, and begin a preventative fungicide spray program. The Task Force website offers many useful tools for homeowners including a Boxwood Blight Management Decision Guide and a list rating Resistance or Susceptibility of Cultivars to Blight.
The VCE Master Gardener YouTube channel also released a playlist of 11 videos discussing this disease:
If you have susceptible cultivars of boxwood on your property, keep an eye out from year to year. If possible, replace these plants with resistant cultivars before they become infected. Otherwise, you will need to consider a preventative fungicide spray program every growing season starting in early spring and hope for the best.
For more information, read the Best Management Practices for Boxwood Blight in the Virginia Home Landscape.