BLACKSBURG—Plant diseases have no regard for history or tradition, and unchecked boxwood blight could change the look of many home gardens and historic sites in Virginia.
That’s why Virginia Cooperative Extension specialists are asking homeowners and home gardeners to take steps to prevent the disease’s spread.
“You definitely don’t want to put boxwood greenery in the compost bin this year,” said Mary Ann Hansen, a Virginia Tech instructor in plant pathology, physiology and weed science and co-manager of the university’s Plant Disease Clinic. “Even with the cold temperatures, the fungus could survive over the winter and spread to nearby plants next spring.”
Winter is a good time to clean up around the yard and garden and remove any plant materials that could spread diseases in the spring. That includes boxwood clippings purchased for holiday decorations.
“Getting rid of the old greenery after the holidays is important,” Hansen said. “The best thing to do is bag it and get it to the landfill. Do not compost it or leave it lying around. Burning it is another option, if allowed by local fire laws.”
Boxwood blight is a fungal disease that starts out as leaf spots with a dark border. Symptoms also appear on stems, which show black streaks. Then the leaves turn brown and fall. Plants can lose almost all their leaves, with just a few green ones remaining at the top. The whole process can happen quickly. According to Hansen, the English boxwood and the American boxwood have no resistance to the disease, and once they become infected there are no fungicides that can save the plants.
“So far, the disease has only been found in certain areas of Virginia,” Hansen said. “It was first found in 2011 in Southwest Virginia, where we have a lot of nursery operations. But it showed up this past fall in the Richmond area in landscapes and a garden center and in a landscape and garden center in Fairfax County.”
Hansen said homeowners and landscape professionals should purchase boxwoods exclusively from nurseries that participate in the Boxwood Blight Cleanliness Program. Those businesses take extra precautions to prevent the disease from entering their stock and participate in regular inspections by the Virginia Department of Agriculture and Consumer Services.
“Some boxwood cultivars also appear to have tolerance to the disease,” Hansen said. Planting those varieties, especially if they are purchased from a nursery participating in the Boxwood Blight Cleanliness Program, can reduce the chances of having to remove diseased plants from a landscape in the long run.
Any infected or suspect greenery should be double-bagged and disposed of, Hansen said, and tools that have been in contact with the greenery should be sanitized with dilute solutions of bleach or disinfectant.
Virginia residents can submit plant samples with symptoms of boxwood blight to the Virginia Tech Plant Disease Clinic through their local Extension offices.
A 2002 study of the Virginia green industry found woody plants like boxwoods were top sellers, accounting for more than half of all nursery sales and almost $400 million in gross receipts.
Media: Contact Norm Hyde, VFBF communications, at 804-290-1146.