Species Information

Water chestnut (Trapa natans) Water chestnut (Trapa natans)
Water chestnut (Trapa natans)
Water chestnut
Trapa natans

  Click here for information at USGS!

  Click here for a quick guide for this species. PDF format!

  • Introduced to U.S. before 1879 by a gardener in Cambridge, Massachusetts, who planted it in several ponds
  • Native to warm temperate regions of Eurasia

  • Rooted, annual, aquatic plant with submerged and surface leaves
  • Surface leaves are waxy and triangular with toothed edges
  • Submerged leaves are feathery and whorled around the leaf stalk
  • Stems can grow up to 16 ft (4.8 m) long
  • Forms dense, floating mats
  • White flowers
  • Nut-like fruit with 2-4 spines

  • Lakes, ponds, slower sections of rivers and streams
  • Prefers nutrient-rich water with a neutral to slightly alkaline pH
  • Can grow in water up to 16.5 ft (5 m) deep, but prefers shallow water (1-6.5 ft, 0.3-2.0 m)

Known Distribution in the Northeast
  • Connecticut, Massachusetts, New Hampshire, New York, Quebec, Rhode Island, Vermont

  • Dense, floating mats restrict light availability, reduce the oxygen content, and displace other emergent and floating vegetation
  • Impedes boating, fishing, swimming and other recreational activities


Water chestnut (Trapa natans)
Water chestnut (Trapa natans)
Water chestnut (Trapa natans)
Water chestnut (Trapa natans)

Protecting the marine and freshwater resources of the Northeast from invasive aquatic nuisance species