European Water Chestnut (Trapa Natans)


Lakes, rivers, streams, and ponds with a soft substrate. It thrives in full sun and nutrient-rich waters. Although most abundant in 2 m of depth it can be found in water depths of up to 4 m.

Introduction and Range Within Canada:

First introduced to the United States in the late 19th century as an "ornamental garden plant" the first record in Canada was from Southwestern Quebec in 1984. Recently established in Ontario, in a bay of the Ottawa River, and along certain south shores of Lake Ontario. It can spread between waterbodies via plant fragments, fruits or seeds that are transported with boats, trailers or other equipment.


Forms extremely large dense floating mats of vegetation that shade out native plants and organisms below. It completely decreases plant biodiversity, making recreational activities like swimming, fishing and boating almost impossible in the infested areas. The hard nut or "fruit" has barbed spines which accumulate on shore and can cause injury when stepped on. Reduced light penetration and plant growth beneath the water chestnut "canopy" combined with a large amount of decomposing vegetation below, lead to decreased oxygen levels which have direct impacts on native plant species and fish.

© Copyright 2019 - Canadian Waterfront Services