How was water chestnut introduced to the Bay watershed?
Water chestnut was first recorded in North America in 1859 near Concord, Massachusetts. It is believed to have spread from ornamental use in ponds. Wild populations have since become established in many locations throughout the northeastern United States, including the Hudson River, Lake Champlain region and Connecticut River valley. In the Bay watershed, water chestnut was recorded in the Bird River in Baltimore County, Maryland, in 1955. The state of Maryland used an herbicide and mechanical removal to control the population. In 1964, it reappeared at the same site, along with 100 acres in the Sassafras River on Maryland’s Eastern Shore. Populations were again removed in 1965 but reappeared in 1997. Why is water chestnut considered to be invasive? Water chestnut infestations have many negative ecological and economic impacts. • Water chestnut threatens native underwater bay grasses by forming a complete canopy with up to three layers of leaves, blocking all sunlight from reaching bay
