Boxwoods are versatile and attractive in the home landscape, so many of us do use them. While not native plants, they perform well here in southern Iowa. Typically they do not require very much attention to look good all through the year.
Unfortunately, a disease called Boxwood Blight has become a problem. It is caused by a fungus. English and common boxwood are particularly susceptible. The infections can be severe in young plants and even kill seedlings.
Symptoms of Boxwood Blight begin with brown leaf spots, straw-colored foliage, sudden defoliation, and black streaks on affected branches. Warm and humid conditions and high moisture are most conducive to the fungus, which can be spread by water, animals, or activities such as pruning.
Anyone concerned about Boxwood Blight can monitor its prevalence in our area quite easily. Use the website and smartphone application version http://uspest.org/risk/boxwood_app. This site includes helpful photos along with information about the level of risk.
It is quite difficult for the home gardener alone to confirm a case of Boxwood Blight. Winter injury or other fungal pathogens may be responsible for leaf bronzing and straw-colored branches. Similar symptoms may occur from nematode infections.
To confirm a diagnosis, it is best to submit a sample to a plant clinic. Iowans may send samples to the Plant and Insect Diagnostic Clinic at Iowa State University. On the submission form, specificy ?check for boxwood blight.? A yes or no assessment of the sample will be completed free of charge. To use this service, go to https://hortnews.extension.iastate.edu/pidc/contact for full information about address and procedures to follow in submitting a sample. While you are there, take a few minutes to browse the site. Whenever a possibly serious problem arises with a tree, shrub, or other plant, it is good to know where to find the plant pathologists with expertise.