Best time to see: Apr to end Nov

Key facts

Our largest grass, spreading via underground hollow stems to form large stands in shallow fresh or brackish water

Typically 2m/6ft in height but can grow much taller, with a feathery, brownish flower spike in late summer

Widespread in fens and swamps, around the edges of lakes and along rivers

Extras

Still in use in Britain for thatching (roofing) buildings

Provides nesting habitat for birds such as reed warbler, bearded tit and bittern, and cover for many other animals