Boxwoods are prized border shrubs in many landscapes — but these sentinels may be under siege.
The fungus that causes boxwood blight (Cylindrocladium pseudonaviculatum) has been con-firmed in two residential landscapes in Atlanta’s Buckhead community. In one landscape the fun-gus has been traced to newly-introduced shrubs from North Carolina; in the other the method of transmission is unknown.
Boxwood blight was first identified in the U.S. in 2011 and appeared in Europe over a decade ago. The disease is categorized by round tan spots with a brown or purple border on the leaves, and black-ening of the stems. Massive leaf drop and death of the shrub follows. The fungus is highly contagious and spreads rapidly, especially in shady, humid and abnormally wet environments. Sticky spores from the fungus are also readily spread through contact with clothing and garden tools. The fungus is not spread by wind.
If the fungus is suspected, authorities recommend bagging and removing the infected shrub at once and sending it to a landfill. Do not compost. All fallen leaf litter should be collected and burned or buried. In addition, all clothing, shoes and tools used in the contact area should be disin-fected. A 10 percent bleach solution or Lysol concentrate disinfectant are recommended for disin-fecting pruning tools. It is also important to avoid pruning boxwoods when they are wet, and to carefully inspect all new shrubs for signs of the fungus.
Authorities also urge sending a sample of the affected shrub to a local extension office for positive ID, since the symptoms of boxwood blight are similar to those of other more common diseases.
Learn more at www.plantpathology.ces.nscu.edu and www.extension.uga.edu.