Landscapers, nursery owners and plant scientists are on the lookout for a new fungus that attacks one of Long Island’s most popular plants: the boxwood.
The boxwood blight has yet to have a significant impact on Long Island, and both the landscaping and research communities are working hard to keep it that way, said Margery Daughtrey, a plant pathologist with the Cornell Cooperative Extension in Riverhead.
“We will have to be quite lucky and vigilant not to bring it in from other areas,” she said.
The deadly disease, calonectria pseudonaviculata, was first spotted in the United Kingdom in 1994, though scientists are unsure of where the disease originally came from.
The blight was not a concern stateside until October 2011, Ms. Daughtrey said, when the disease was found in Connecticut and North Carolina.
Since the disease had already been well-documented in Europe, scientists in the U.S. were able to share information about the disease quickly, she said. The fungus then spread to a few other states, like Maryland, Virginia and Oregon, which are large exporters of boxwood plants. That’s kept scientists on high alert for cases in new states.
The first cases of the disease in New York were found at two garden centers in December 2011.
The fungal disease attacks the plant at the point of contact, causing signature black spots on the leaves.
“We’re used to seeing dead foliage on boxwoods for a bunch of reasons, including winter injury, but this is a disease where the leaves usually fall off,” Ms. Daughtrey said.
Bare boxwood twigs are a good indicator that the blight is present, she said, adding that gardeners may also notice thin black streaks running down the sides of twigs on blight-infected boxwoods.
Since the disease was first spotted in 2011, no more than a dozen cases of boxwood blight in the landscape have been identified on Long Island, she said, adding that the infected plants were likely circulated before word of the disease spread. None of those cases occurred on the North Fork, she said.
No cases have yet been seen in production at nurseries on Long Island, she said.
“I think our nurseries have escaped contamination up until now,” Ms. Daughtrey said. “I don’t know if they always will but they’ve been lucky so far.”
But the growing demand for boxwood — a popular deer-resistant plant — on Long Island means that may not always be the case.
“Long Island doesn’t grow as many boxwoods as it needs,” Ms. Daughtrey said. “Over time it will get moved along a lot.”
Federal funding was recently approved to research the disease, she said, adding that scientists are curious to learn why some boxwood species are more resistant to it than others.
Landscapers who have been affected by the disease have worked with the Cornell Cooperative Extension to eradicate the blight, Ms. Daughtrey said.
Most nurseries are aware of the new blight and are taking steps to prevent it from reaching the North Fork, Ms. Daughtrey said.
Lou Caracciolo, owner of Shade Trees Nursery in Jamesport, said his company is screening the sources of its boxwood plants. If a supplier is from a state where infected plants are known to exist, the nursery will shop elsewhere.
“Basically, all you can do is just monitor,” Mr. Caracciolo said. “It’s a matter of infected plants coming in.”
Yet other nurseries in the area haven’t been able to find any suppliers of healthy boxwood. Homeside Florist and Garden Center in Riverhead just isn’t selling any boxwood this year.
“We can’t get healthy ones,” an employee explained.
At Twin Pond Nursery on Sound Avenue, several rows of boxwood plants — five different varieties in all — grow in one of the fields. An employee said this is the third year the nursery has grown the plants.
“The problem is there’s no fungicide for [the blight],” he said, adding the plants there came from Delaware.
Still, Ms. Daughtrey said there are steps consumers can take to keep the blight in check. Infected plants will be more recent purchases from within the last three years, she said. English boxwoods, one of the more expensive varieties, are most susceptible.
From now on, homeowners should plant boxwoods in open spaces instead of in the shade, since sunlight will help prevent damp conditions that helps the disease flourish.
Consumers and landscapers should also be most wary during cooler, wetter times of the season, she said. Scientists will be watching this season to see how the fungus behaves in drier conditions.
“We need to live with it for a while see how it behaves,” she said. “It’s new. We really don’t know what to expect.”