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Conium maculatum

Hemlock flowerhead

Identifying Hemlock

Hemlock has umbrella-like white flowers, which appear in dome shaped rounded clumps in summer, which are usually 2-5 cm across.

One of the easiest ways to identify Hemlock is by its stems – which are mostly large, hairless and have purple spots or blotches along their length.

The leaves are fine and look similar to ferns – lacy and similar to that of others in the carrot family.

Hemlock is one of the UK’s tallest native umbellifer species, growing up to 2 metres and can smell quite unpleasant. The unpleasant smell is caused by the poisonous chemicals and acts as a deterrent to animals.

All parts of this plant are poisonous and all members of this family should be treated with caution, notably because Hemlock can be easily mistaken for Cow Parsley and other harmless members of it’s family.

A close up of the blotched stem of the Hemlock

Similar Species

The hairless purple blotched stems are key to identifying this plant (pictured), as well as the extremely unpleasant smell.

It can also be distinguished through it’s flowering time, as it flowers after Cow Parsley, and around the same time as Hogweed, in June and July.

Hemlock could be confused with Hogweed, Upright Hedge-parsley and Hemlock Water-dropwort (also poisonous).


Likes damp places such as along streams, but can also be found growing in dry habitats such as scrubland and waste land.


Widespread in most of England and the lowland areas of Wales, also found in some southern or coastal areas of Scotland.

Did you know?

  • Pollinators love it! Hemlock is a larval food-plant for several moth species, and a host to a hidden world of specific fungi species. These have all evolved alongside it to be able to tolerate the toxins.
  • Common names include Mother dies, Kexies and Woomlicks.
  • In 399 BC, Greek philosopher Socrates was found guilty of corrupting the young minds and for not believing in the gods of the state. He was sentenced to death and forced to drink an infusion of Hemlock.


We must remember that almost all wild plants & fungi are no danger to us as we go about our days. Plants are the foundation of life, and we need a world rich in plants to tackle the twin climate and biodiversity crises.

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