Boxwood Blight - New Dreaded Boxwood Disease

Boxwood blight is a relatively new disease that ruins the appearance and health of boxwoods and pachysandras. Boxwoods are popular evergreen shrubs primarily used for hedge and border planting. Pachysandras are close relatives, but instead of growing upwards, these are evergreen ground cover plants that grow close to the ground.

Boxwood blight can and does effect both of these shrubs, robbing them of their leaves and ability to fend off other types of diseases.

Fungal Disease

Boxwood blight is a fungal disease caused by the organism Cylindrocladium buxicola. The disease goes by several other names, including boxwood leaf drop and box blight, but the results are the same - a stunted, misshapen shrub that with yellow and missing leaves.

U.K. To U.S.

Boxwood blight was first discovered in the U.K. in the mid-1990's and didn’t show up in the United States until two decades later. The fungal disease showed up in the southern part of the United States in a North Carolina nursery in 2011, and has spread northward to the state of Massachusetts. Boxwood blight has not limited itself to the U.K. or to that particular section of the U.S., it has also showed up in isolated regions all across the U.S.

Blight Symptoms

Symptoms are similar to other diseases that attack boxwoods, making it difficult to diagnose and treat immediately. The first sign of the fungal disease is brown spots on the shrub’s leaves. Soon after the brown spots appear, the boxwoods will drop the spotted leaves and the woody stems begin to die back. The remaining leaves will turn a sickly shade of yellow because the shrub has been weakened by the fungus and can no longer provide the needed nourishment to the leaves.

No Root Involvement

The only good news about boxwood blight is that is does not involve the roots system. Only the portion of the shrub which is above ground is infected, so most of the time an infected boxwood can be saved by cutting it back to near ground level and allowing it to re-grow.

A shrub doesn't usually die of boxwood blight disease, a secondary infection is typically the killer. After repeatedly losing its leaves, a boxwood will become so weak that it has no resistance to other diseases.

For pictures of dreaded Boxwood Blight disease, visit The Connecticut Agricultural Experiment Station.

Read our blog post on How to Diagnose and Treat Boxwood Blight.