Water Chestnut
(Trapa natans)
*Not detected in Michigan*
WATCH LIST - PROHIBITED IN MICHIGAN
Report this species to:
DEQ Aquatic Invasive Species Program DEQ-WRD-ANC@michigan.gov 517-284-5593
If possible, please take one or more photos of the invasive species you are reporting. Also make note of the location, date and time of the observation. This will aid in verification of your report. You may be asked to provide your name and contact information if follow-up is needed.
- Or - use the Midwest Invasive Species Information Network (MISIN) online reporting tool
- Or - download the MISIN smartphone app and report from your phone - http://www.misin.msu.edu/tools/apps/#home
Identification:
- 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
Michigan DNR
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
MORE INFORMATION:
Water Chestnut Invasive Species Alert - Printable PDF
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.