Water chestnut (Trapa natans)

Water chestnut Common Names: European water chestnut, water nut

Description: This species is listed on the Michigan prohibited aquatic plant list. The toothed, triangular leaf with inflated petioles is distinctive throughout the growing season.

Habit: Aquatic; rooted; floating; mat-forming annual in shallow or deep freshwater; grows in depths of up to 4.6 m (15 ft).

Leaves: Toothed floating leaves have inflated petioles and are arranged in a rosette, while its submerged leaves are feathery.

Stems: Cord-like; spongy; buoyant; can reach lengths up to 16 ft; anchored to the bed of the waterbody by branched roots.

Flowers: Small, white in color, 4 petals; bloom from July to first frost.

Fruit and seeds: Spiny nut appears where flowers were. 2-4 1.3 cm (1/2 in) long, sharp, barbed spines.

Habitat: Native to Europe and Asia. Found in freshwater lakes, ponds, canals, and slow waters.

Reproduction: By floating rosettes and its single-seeded spiny nut, which attaches to boats or animals. The spines can pierce shoes.

Similar species: Singhara chestnut (Trapa bispinosa).

Monitoring and rapid response: Complete removal of plants is imperative. Eradication is difficult because seeds may lay dormant for up to 12 years.

Credits: The information provided in this factsheet was gathered from the Center for Invasive Species and Ecosystem Health, the Michigan Natural Features Inventory and the New York Sea Grant.

Individual species images that appear with a number in a black box are courtesy of the Bugwood.org network (http://www.invasive.org).Individual photo author credits may not be included due to the small display size of the images and subsequent difficulty of reading the provided text. All other images appear courtesy of Google (http://images.google.com).

Common Name:

Water chestnut

Scientific Name:

Trapa natans


(Water chestnut)





USDA Symbol: