Water lettuce

Water lettuce

Pistia stratiotes

Common Name:

Water lettuce

Scientific Name:

Pistia stratiotes

Alternative common names:

Waterslaai (Affrikaans).


Water lettuce is a floating herb in rosettes of grey-green leaves, rosettes occurring singly or connected to others by short stolons. Perennial, mat-forming, usually free-floating aquatic plant, seldom exceeding 150-200 mm in diameter; plants consist of a rosette of leaves with a tuft of long, fibrous roots beneath and resemble floating lettuces

Additional Information

Where does this species come from?

South America (Brazil)

What is its invasive status in South Africa?

NEMBA Category 1b

Where in South Africa is it a problem?

Limpopo, KwaZulu-Natal, and Mpumalanga.

How does it spread?

The seeds float and are therefore most commonly dispersed by water. Entire rosettes may also be spread by water and wind movement and by boats. They are also commonly dispersed in dumped aquarium or garden waste

Why is it a problem?

Forms dense mats which completely cover a water surface. The mats clog waterways & irrigation equipment, reduce waterflow, impede navigation, fishing & other recreational activities, and provide a breeding place for mosquitoes and bilharzia-carrying snails.

What does it look like?

Leaves: Pale yellow-green, narrower at the base, rounded, straight or notched at their tips
Flowers: Pale green or white, inconspicuous.
Fruit/seeds: Small, green capsules.

Does the plant have any uses?

Has often been grown as an ornamental in lakes, ponds, aquaria and gardens. It is often used in tropical aquariums to provide cover for fry and small fish

Leave a Reply