Water chestnut is a fast-growing, floating annual that can grow to 16 feet in water depth. It has feathery, submersed leaves and triangular, toothed, floating leaves that are glossy. Floating leaf stalks have visible bulbous bladders and commonly form rosettes. Flowers with four white petals normally bloom in July. The most distinctive trait of this plant is its thorny four-spined nutlets which mature in late summer. Reproduction occurs from these very sharp nutlets and from fragmentation of the rosettes.
Confirmed observations of Water chestnut submitted to the NYS Invasive Species Database. For more information, visit iMapInvasives
Water chestnut is found in quiet, high nutrient waters with soft substrate and neutral to alkaline pH.
Threats & Impacts:
Impenetrable mats of water chestnut can cover large expanses of water, altering water quality and clarity, eliminating the growth of native aquatic plants, and making boating, fishing, and swimming hazardous.
Small populations can be controlled by hand pulling prior to the release of the nutlets. Large infestations have been controlled in the Northeast by the use of mechanical harvesters or the application of aquatic herbicides.