An official website of the United States government.

The .gov means it’s official.
Federal government websites always use a .gov or .mil domain. Before sharing sensitive information online, make sure you’re on a .gov or .mil site by inspecting your browser’s address (or “location”) bar.

This site is also protected by an SSL (Secure Sockets Layer) certificate that’s been signed by the U.S. government. The https:// means all transmitted data is encrypted — in other words, any information or browsing history that you provide is transmitted securely.

National Invasive Species Information Center
U.S. Department of Agriculture
Home / Aquatic Invasives / Aquatic Plants / Water Chestnut

Water Chestnut

View all resources
Water chestnut
Water chestnut, flowers - Photo by Leslie J. Mehrhoff; University of Connecticut
Scientific Name: 

Trapa natans L. (ITIS)

Common Name: 

Water chestnut, water nut, water caltrop

Native To: 

Eurasia and Africa (Hummel and Kiviat 2004)

Date of U.S. Introduction: 

1870s (Hummel and Kiviat 2004)

Means of Introduction: 

Ornamental (Hummel and Kiviat 2004)

Impact: 

Forms dense mats that displace native species and interfere with recreational activities (Hummel and Kiviat 2004)

Distribution / Maps / Survey Status

Early Detection & Distribution Mapping System (EDDMapS) - European Water Chestnut
University of Georgia. Center for Invasive Species and Ecosystem Health.
Provides state, county, point and GIS data. Maps can be downloaded and shared.
Nonindigenous Aquatic Species Database: Point Map - Water Chestnut
DOI. USGS. Wetland and Aquatic Research Center.
Provides detailed collection information as well as animated map.

Images

Google Images - Water Chestnut
Google.
Invasive.org - European Water Chestnut
University of Georgia. Center for Invasive Species and Ecosystem Health.

Videos

YouTube - Wanted: Water Chestnut
Google. YouTube; Stony Brook-Millstone Watershed Association Education (Central New Jersey).
YouTube - Water Chestnut

Google. YouTube; Riverbank Media.

Selected Resources

The section below contains highly relevant resources for this species, organized by source. Or, to display all related content view all resources for Water Chestnut.

Council or Task Force
Fact Sheet: European Water Chestnut (Feb 2018) (PDF | 2.24 MB)

Alberta Invasive Species Council (Canada).

See also: Fact Sheets for more information about individual invasive species, including those listed as "Prohibited Noxious" and "Noxious" under the Alberta Weed Control Act

Partnership
Global Invasive Species Database - Trapa natans (aquatic plant)
IUCN. Species Survival Commission. Invasive Species Specialist Group.
Invaders Factsheet: European Water Chestnut

Ontario's Invading Species Awareness Program (Canada).

Invasive Plant Atlas of the United States - Water Chestnut
University of Georgia. Center for Invasive Species and Ecosystem Health.
Invasive Species Compendium - Trapa natans
CAB International.
NEANS Panel Online Guide - Water Chestnut
Northeast Aquatic Nuisance Species Panel.
New York Invasive Species Information - Water Chestnut

New York Invasive Species Clearinghouse.

Federal Government
Silvio O. Conte National Fish and Wildlife Refuge - Water Chestnut (Jan 2004) (PDF | 236 KB)
DOI. Fish and Wildlife Service.
National Exotic Marine and Estuarine Species Information System (NEMESIS): Chesapeake Bay Introduced Species Database - Trapa natans

Smithsonian Institution. Smithsonian Environmental Research Center. Marine Invasions Research Lab.

Nonindigenous Aquatic Species Database: Fact Sheet - Water Chestnut
DOI. USGS. Wetland and Aquatic Research Center.
Provides distribution maps and collection information (State and County).
PLANTS Database - Water Chestnut
USDA. NRCS. National Plant Data Center.
U.S. National Plant Germplasm System - Trapa natans

USDA. ARS. National Genetic Resources Program. GRIN-Global.

International Government
NSW WeedWise: Water caltrop
New South Wales Department of Primary Industries (Australia).
Fact Sheet: European Water Chestnut (PDF | 464 KB)

Ontario Ministry of Natural Resources (Canada).

See also: Invasive Species Fact Sheets for more resources
Invasive Plants: Prohibited Invasive Plants - Floating Water Chestnut

Business Queensland (Australia).

State and Local Government
AIS Control Plan: European Water Chestnut (Nov 2020) (PDF | 310 KB)

Pennsylvania Fish and Boat Commission.

See also: Aquatic Invasive Species for more action plans

Environmental Fact Sheet: Water Chestnut (2019) (PDF | 651 KB)

New Hampshire Department of Environmental Services.

See also: Publications - Invasive for more resources

Freshwater Aquatic Invasive Species in Rhode Island: Water Chestnut (Nov 2017) (PDF | 942 KB)

Rhode Island Department of Environmental Management. Office of Water Resources.

See also: Aquatic Invasive Plants for species of concern

Animals, Plants, Aquatic Life - Water Chestnut

New York Department of Environmental Conservation.

Aquatic Invasive Species: Water Chestnut

Maryland Department of Natural Resources.

Invasive Plants in Pennsylvania: European Water Chestnut (PDF | 107 KB)

Pennsylvania Department of Conservation and Natural Resources.

See also: Invasive Plant Fact Sheets for plant species (trees, shrubs, vines, herbs and aquatic plants) that have impacted the state's natural lands

Water Chestnut

Wisconsin Department of Natural Resources.

Academic
Aquatic Invasive Species in the Chesapeake Bay - Water Chestnut (Sep 2013) (PDF | 101 KB)

Maryland Sea Grant.

See also: Six Species of Concern for more fact sheets
Factsheet: Water Chestnut (2013) (PDF | 219 KB)

Pennsylvania State University. Pennsylvania Sea Grant.

See also: Aquatic Invasive Species: Resources for additional species information

Weed Control in Natural Areas in the Western United States: Water Chestnut (2013) (PDF | 279 KB)
University of California. Weed Research and Information Center.
See also: Weeds in Natural Areas for more information sheets
New York Sea Grant Fact Sheet - Water Chestnut (Trapa natans) in the Northeast (Feb 2006) (PDF | 350 KB)
New York Sea Grant.
See also: Aquatic Invasive Species: Publications
Introduced Species Summary Project - Water Chestnut
Columbia University. Center for Environmental Research and Conservation.
Maine Invasive Plants Bulletin: Water Chestnut
University of Maine. Cooperative Extension.
See also: Maine Invasive Plants & Entire Series for entire series of 22 fact sheets and invasive plants brochure (available in HTML/PDF or for purchase)
Professional
Maine's Interactive Field Guide to Aquatic Invaders and Their Native Look Alikes - Water Chestnut
Lake Stewards of Maine.
Special Note: Formerly known as the Maine Volunteer Lake Monitoring Program.

Citations