Invasive privet is a popular landscape choice for the new houses being built along the shoreline of the East Passage of Narragansett Bay in Portsmouth, R.I. (Frank Carini/ecoRI News)
Rhode Island is the only New England state that doesn’t have a list of invasive plants that are banned, or at least identified in Connecticut’s case. The Rhode Island Department of Environmental Management’s invasive plants webpage simply notes some of the damage nonnative species can cause, but only mentions two: phragmites and black swallow-wort. Neither are sold at nurseries, although the latter was historically sold as an ornamental vine here and elsewhere.
Today, the European species (Cynanchum louiseae), also known as dog-strangling vine, has overrun acres of space that once belonged to native plants, such as milkweed. Monarch butterflies rely on native milkweed as a major food source and a place to lay their eggs. Female monarchs, however, can confuse milkweed with the invasive black swallow-wort. Larvae that hatch on black swallow-wort can’t mature because of a toxin produced by the nonnative look-alike…