32 Records

Water Chestnut is an invasive species in Maryland (MISC 2022). Water Chestnut has been a focus of eradication efforts in Maryland since the 1960s. Major efforts to remove the plants by mechanical harvesting and the use of herbicides have greatly reduced the population. Water Chestnut can still be found in northeastern Maryland, particularly along the Sassafras River and Lloyds Creek. It has also been observed in recent years in non-tidal lakes and ponds including Urieville Lake. Any observations should be reported to the Maryland Department of Natural Resources immediately. You can find more information about Water Chestnut on the MD DNR page. A second species, Trapa bispinosa has been found in the Potomac River basin in Virginia. This species also has the potential to become an invasive pest in Maryland should it be introduced.

Water Chestnut grows in freshwater (and slightly brackish) habitats where it can grow floating on the surface of the water. The diamond-shaped leaves have a long petiole, often with a thickened ‘float’. The plant spreads by fragmentation of plants and by seeds produced in 4-spined, pyramidal fruits.