This plant is widespread but only locally common throughout the UK and Ireland.
All parts of this fast-growing plant of wetlands and river margins is poisonous. If cattle eat the roots the result can be fatal.
The common name comes from the fact that the tuberous root is connected to the main plant by only a relatively thin linking fibre.
Hemlock water-dropwort flowers mainly in June and July. It is a perennial umbelifer and can sometimes reach shoulder height. Because it is such a poisonous plant, the stems should not be used for making peashooters.
The pictures on this page were taken in West Wales in July.