Water Lettuce

Also known as:
Tropical Duckweed

General description

Floating freshwater perennial resembling thick-leaved lettuce. Short stem below densely crowded rosette. Fan shaped ribbed bright green leaves, densely hairy. Basal leaves lie flat on water or cluster vertically. Flowerhead with tiny flowers shaped like miniature arum lily. Fruit oval, <10cm long; wrinkled disk-like seeds. Clusters of branched roots <45cm long under water.

Fertile water ~ 20ºC for most of year. Very frost tender.

Rapid local spread by runners across the water surface. Seeds & plants by water.

One of the world’s worst aquatic weeds. Dense surface cover restricts recreational & livestock access to water, increases water loss through transpiration, impedes drainage, causes flooding.

Site management

Report all sites to MAF.

Recommended approaches

Control under MAF direction. Hand clearance is effective.

Caution: when using any herbicide or pesticide PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.

Search tags

RPMS status

Surveillance - Whole Region
National Pest Plant Accord species - nationwide
water lettuce - Main species image