This species spreads mainly through vegetative reproduction (3), but flowers are occasionally produced in shallow water exposed to the full sun (2). When covering the entire surface of a pond, it can make the water appear solid, and in parts of the north-west of England children were scared away from such ponds by the myth of Jenny Green-teeth, a pond elf or monster whose presence was indicated by duckweed; she was said to lure children into ponds and drown them (5).