Poisonous plants – hemlock water-dropwort

Oenanthe crocata

Hemlock water-dropwort leaf

Hemlock water-dropwort (not to be confused with its equally toxic cousin hemlock (conium maculatum) is common in shallow water and wet ground throughout the UK, especially ditches,  slow-flowing streams and on foreshores. It has been mistaken for wild celery or water-parsnip – be very careful when IDing either of these for eating, or indeed any member of the carrot family. All parts of hemlock water-dropwort are potentially deadly. Look out for distinctive carrot family leaves  (3-4 times pinate at base) growing from or near water, strong unpleasant smell when broken (like acrid celery), hairless hollow grooved stem and white swollen roots.

Both foragers and dog walkers should familiarise themselves with the distinctive “dead man’s fingers” of hemlock water-dropwort roots. These are often exposed on river banks or washed up after floods or high tides. Most years they result in the deaths of several dogs around the UK after winter storms.

Dead Men’s Fingers – the roots of Hemlock water-dropwort. I found these washed up after a storm

Regardless of its toxicity, I am very fond of hemlock water-dropwort. Its growth is remarkably vibrant from December through to June. In dark winter months where not much is growing, it is easy to spot by its vigorous green growth in damp spots – often growing directly from water.

Hemlock water-dropwort, January

Winter is a good time to “tune in” to it, before it gets mixed up with other plants. Be particularly careful if harvesting watercress or pie cress in the spring – they are regularly entwined with HWD.

Hemlock water-dropwort, watercress and pie cress, sharing a ditch. Careful now!

In the spring and summer, its rounded umbels of small white flowers are a rich source of food for hoverflies and other insects, and wetlands can look spectacular festooned in their white baubels.

Hemlock Water-dropwort “water meadow”, June

HWD has a fascinating history. Its very toxicity once held it in high esteem when capital punishment and euthanasia were more common, and easy methods of execution valued. A “sardonic” smile, is a direct reference to the widespread use of HWD in Sardinia where a decoction of its roots were used to administer death sentences. As this powerful muscular convulsant stopped the victims heart, it would also act on facial muscles, drawing the face into a grim “Sardinian”, or sardonic, smile.

A sardonic death mask from North Africa

In appropriate doses, the effect of the active compounds on muscles can have a relaxing effect, and I perhaps research is currently underway into the use of HWD as a botox substitute…

Botox or death mask?

Related articles:

•  “The Day I Ate a Deadly Plant: The Spectrum of Edibility“
•  View more poisonous species
• An Introduction to the Carrot/Apiaceae Family for Foragers