Boxwood Blight Attacking Neighborhoods
Adapted by Joanna E. Radford, Extension Agent with N.C. Cooperative Extension from Leah Roberts, Plant Pathologist with North Carolina Department of Agriculture
Homeowners with boxwoods in their landscape may notice the plants losing leaves at an alarming rate recently. Leaf drop, along with leaf spots, and balck stem streaks are classic symptoms of an important boxwood disease known as blight. Boxwood blight has been in North Carolina since 2011 and continues to spread. The disease becomes especially severe following rainy weather.
Boxwood blight is caused by a fungus that produces very sticky, microscopic spores. Though they cannot be seen, theses spores readily stick to hands, shoes, pruning shears, and other tools, which are all important means of disease spread. Both home and professional landscapers should sanitize their tools between landscapes and even within different areas of a single landscape when working with boxwoods. Fallen leaves also contain fungal tissue from the pathogen and the disease can be spread by moving fallen leaves about with mowers or leaf blowers.
If you notice symptoms of boxwood blight, contact your county horticulture Extension agent to get a definitive diagnosis. Infected plants can be removed and replaced with Japanese hollies or similar species which are not hosts of boxwood blight. As an alternative, homeowners could prune out infected material and spray fungicides to protect plants that are not yet affected. County Extension agents are the best source for information regarding fungicide application and timing. Once a positive diagnosis of blight has been made, the plants will not be cured, but they may recover to the degree that they are appealing enough to remain in the landscape. It should be noted, however, that leaf drop will likely occur in extremely we seasons, even with the best fungicide spray program. The continual cycle of leaf drop and regrowth will become a fact of life when living with boxwood blight. Despite the challenges posed by blight, boxwoods remain a classic, evergreen plant with utility in foundations, hedges, topiaries, and even as Christmas greenery.