There’s a curtain of verdant foliage along one of the little waterways feeding the lake in Dover’s Silver Lake Park. It drapes the trees and shrubs abutting the pathway leading from the park entrance to one of the many picnic pavilions.
To the untrained eye, it’s beautiful.
To environmental scientists, it’s a nuisance.
That curtain of green actually is a stand of the porcelain berry, a plant native to Asia, but an invasive pest here in Delaware. Engineers and scientists with the city of Dover, the state Department of Natural Resources and Environmental Control, and a group of volunteers spent Aug. 19 and 20 trying to help native vegetation regain a foothold in the park by cutting back the invading, non-native flora.
“These plants don’t have the natural enemies found in their original habitats,” said Rob Line, program manager for the Delaware State Parks’ Environmental Stewardship Program, which helps oversee the volunteers. “There’s nothing to hold them back. Our native plants don’t have that advantage.”
Well-meaning people who use them for ornamentation in gardens and yards have inadvertently introduced these alien plants throughout the years, Line said. The plants are popular because they’re attractive to the eye and because they grow very quickly.
Fast growth is natural for any organism situated in a friendly environment where animals that normally feed on it or diseases that could kill it don’t exist, he added.
“Plants native to Delaware, they have to deal with that,” Line said, as part of the natural order. For example, he noted, there are more than 200 insects that can attack native oak trees in the First State. For a tree such as the Norway maple, which is not indigenous to Delaware, there only are 14 local insect species that can harm it.
“In Norway,” Line said, “they have a lot more than that.”
In addition to the porcelain berries, Line and the volunteer teams were working to eliminate areas of phragmites and the multiflora rose, also types of invasive plants.
They spent the two days either cutting the plants down or spraying them with environmentally safe herbicides. In one case, they managed to pull a shroud of berry vines from a small tree. While the tree still lived, it was misshapen and almost denuded of leaves.
The reason: the berry plants enveloping most of the tree had kept away life giving sunshine. Only a small area of leaves had managed to peek through, barely enough to keep the tree alive.
