Rachel Lambert: forager, author, guide

Hemlock Water Dropwort

I thought it was about time I wrote about this highly poisonous plant; Hemlock water dropwort (Oenanthe crocata). Any plant with 'hemlock' in its name is a fair sign to avoid it. While I normally write about wild, edible plants, sometimes it is good to know what NOT to eat.

In this blog you'll discover how to identify hemlock water dropwort, where it grows, why to avoid it, and a little about its uses too.

Why learn about hemlock?

Those of you who know me probably know that I don't know much about poisons - I'm much more interested in food! Though over the years I've learnt a fair amount about this plant and I often introduce it on my foraging courses and bespoke foraging experiences to help people understand what not to eat.

Fine toothed leaves of Hemlock water-dropwort on a foraging course in Cornwall

I love teaching people about edible plants; how to identify, use them and generally how to connect and appreciate nature. I love watching people go off inspired and confident to try wild foods. I love it when there's humility and people also leave plants because they're following the golden rule: IF YOU:RE NOT SURE, DON'T PICK IT.

Though there is another way that can help too: Learn about poisonous plants and the ones to completely avoid. Here I am focusing on Hemlock Water Dropwort.

Three different stems of Hemlock water dropwort on a foraging course in Cornwall

What does Hemlock Water Dropwort look like?

Hemlock water dropwort is a member of the Umbellifer or Apiaceae (Carrot) family which all have a similar structured flower-head in a shape of a parasol or umbrella. It grows up to 1.25 metres tall.

The leaves of plants in this family can vary a lot, as well as vary within one species too. For example, the image above are all leaf stems from three different plants of Hemlock Water Dropwort. Each at a different growing stage. Each leaf or lobe of each leaf, is toothed.

I often describe the leaves as looking like coriander leaves, flat-leaved parsley or carrot leaves. There is also a fine-leaved water-dropwort variety, but Hemlock Water-dropwort is the most common here in the UK.

The stems of Hemlock Water-dropwort are hairless, hollow and grooved (ridged). Like many plants, they may be green or tinged with purple.

The stems of Hemlock Water-dropwort are hairless, hollow and grooved (ridged). Like many plants, they may be green or tinged with purple.

Where does Hemlock Water-dropwort grow?

It thrives in water; by streams, rivers, ponds, ditches and damp, boggy areas of fresh water. It can also be found on dry ground several metres away from water, or on dry patches that are wet in the winter or rainy season. It is very common in the South West of Britain and is present across Europe and North Africa.

Is Hemlock Water-dropwort harmful to animals?

Yes. This plant can be harmful to dogs, cattle and all animals if eaten. Though because of its pungent smell, animals tend to avoid it and not eat or graze on it. My dog is a natural scavenger (seen here very muddy in a stream with hemlock water-dropwort growing!) but has never eaten this plant.

Paddy dog in stream with hemlock water-dropwort on a foraging course in Cornwall

How poisonous is Hemlock water-dropwort?

Hemlock water-dropwort is considered to be the most poisonous plant in the UK. All parts of the plant are poisonous and symptoms can include; vomiting, seizures, paralysis, hallucinations and death. The worst case I heard off involved a young man in a coma, having had 3 heart attacks - that was from eating the roots which are potentially the most fatal. He survived, but the plant did not give him an easy time.

Less extreme cases come from nibbling the leaves, though it is still advised to seek medical help and take some of the plant with you. In some cases children or adults have been put on a drip or observed overnight to ensure the plant is flushed out of the body and hasn't done any internal damage. Please don't eat it!

unopened buds of hemlock water-dropwort on a foraging course in Cornwall

Are there any benefits to Hemlock water-dropwort?

Every plant has a purpose and numerous benefits. Hemlock water-dropwort is chosen by gardeners for its architectural qualities, because it can thrive in damp meadows and gardens and is not prone to disease or pests.

It is also a plant food for various beetles and weevils, such as Prasocuris phellandrii - a beautiful metallic green, blue or brassy coloured beetle. Several parasitic organisms use it as a host plant and a whole array of types of fungus benefit from this plant when it is both living and decomposing .

Hemlock Water Dropwort as a Pollinator

As a member of the Umbellifer plant family, this plant provides a fantastic food for pollinators. Bees and other pollinating insects actually have a way a grade the food quality of each plant. This enables them to weigh up the value verses the energy used to travel to and feed off each plant. Umbellifers such as Hemlock are considered of high value: a grade 2, from a scale of 1-5, 1 being of the greatest value.

Details of hemlock water dropwort leaf on a foraging course in Cornwall

To summarize, some plants look rather attractive, edible even, and hemlock water dropwort is one of them. Don't eat any plants that you are unsure of their identity and be particularly careful around members of the umbellifer family and plants growing near water. Never eat Hemlock water-dropwort, if you'd like to experiment with plants there are plenty of tasty wild foods to experience instead.

10 comments on “Hemlock Water Dropwort”

  1. thanks took spectre and just found out I have this poisonous plant in my garden!!
    I have a child to think of I thought it was going be a sunflower the thickness of its stem!!

    1. A wonderful opportunity to learn together about plants and respect that this plant is good for pollinators but poisonous for us. X

  2. Hemlock water droplet has become very common here in Lancashire. I did not have it at all along the banks of the River Darwen when I came here in 1975. This is down to climate change.
    Chris Mortimer

    PR5 0SS

    1. Hi Chris, would you like to explain what you mean by 'this is down to climate change' - I'm sure people would like to hear your knowledge/take on this.

  3. Water dropwort is flourishing in many streams and rivers throughout the UK, more than ever, especially here in West Wales.
    I've been told by the Rivers Trust that it's a pollution indicator plant, and flourishes when there are high nutrient levels (nitrogen/phosphorus usually from sewerage treatment or run off from 'muck spreading' (the water authorities are one of the biggest polluters in the UK, farming is next)
    I warned my neighbour (City person) when he started pulling out all the dropwort from his stretch of our stream and strimming it from the banks that it was highly poisonous and he replied "if it was that dangerous they'd put signs up warning us"

    1. Thanks for sharing Klaran, and for trying to inform your neighbour! It's really helpful to have you pass on the perspective of the Rivers Trust

  4. Ive got an abundance of it on my garden pond, year on year I have admired it for it beauty and benefit to the pollinators which enjoy it during the summer.... NOW I want it gone. I dont use herbicides of any kind in my garden but I think that is about to change once I find one which will not impact on the wildlife of the pond. I cant pull it out for the simple reason there is so much of it.

    1. Why do you want it gone??? It's a fantastic pollinator, brilliant for wildlife, and a stunning plant to look at. Just not good for humans to eat.

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