- Green, floating leaves with sharply serrated edges
- Leaves form a densely crowded rosette
- Small, white 4-petaled flowers
- Produce a hard “woody” nut surrounded by sharp barbed spines
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org - Water chestnut with seed
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org - Water chestnut cluster
Habitat: While water chestnut shows a preference for shallow, nutrient-rich lakes and rivers, it can grow in mucky substrate
Native Range: Europe, Asia, and Africa
U.S. Distribution: Naturalized in the northeastern United States
Local Concern: Water chestnut forms dense mats that shade out native aquatic vegetation, leading to a decrease in biodiversity. Decomposition of vegetation below a dense mat decreases oxygen levels and can cause fish kills. Boating and other recreational activities become almost impossible in an area invaded by water chestnut.
Other Common Names: European water chestnut, horned water chestnut, water caltrop
MDARD Weed Risk Assessment for Water Chestnut (Trapa natans) - This document evaluates the invasive potential of the plant species using information based on establishment, spread and potential to cause harm.