The boxwood blight, also known as box blight or boxwood leaf drop, is a fungal disease of boxwoods that was first seen in the US in October 2011. It was initially discovered in North Carolina and Connecticut, but by early 2012 it had also been found in Maryland, Massachusetts, New York, Ohio, Oregon, Pennsylvania, Rhode Island and Virginia. We have since noticed its appearance in the Bucks County Pa area.
So far it seems as though most commercial boxwoods, especially English and American, are highly susceptible to the disease, as is pachysandra, which is in the boxwood family. This disease doesn’t normally kill the host but causes significant defoliation and branch die-back. If boxwood blight is present your initial indication will be dark or light brown spots on leaves. The leaves will then turn brown or straw color and fall off. The stems of the boxwood will also develop black or dark brown lesions.
At Peter Benz Landscaping, we highly recommend that any new boxwood brought onto a property is quarantined for a least one month after leaving the nursery. Many nurseries are spraying boxwoods with preventive fungicides that can temporarily mask the symptoms of the disease. After 2 to 3 weeks the fungicides will wear off and the disease may cause a rapid decline in affected plants.
The boxwood blight spores spread through wind, rain splash, and overhead watering. It can also jump from property to property on contaminated tools, such as pruning shears. We recommend that any tools used on boxwoods be sterilized with alcohol or a 20 percent bleach solution. Any clippings should also be burned or buried instead of taken to a dumping facility or composted. Boxwood blight can survive for five years in fallen boxwood leaves.
As of right now there is no cure for this fungal disease, although research is ongoing. Fungicides can help prevent the spread of boxwood blight, but to be effective they must be applied frequently and to the entire plant including, leaves and stems. If you noticed an infected plant you should remove the whole plant and place it into a plastic bag. Contact Peter Benz Landscaping so we can inspect any boxwoods on your property that may be contaminated and treat if necessary.