How to identify Hemlock Water Dropwort

People have died from eating all parts of Hemlock water dropwort.

Hemlock water dropwort is a member of the Apiaceae (Carrot) family. Which contains some very toxic plants.

It is considered the most toxic plant growing in Britain.

It contains a powerful neurotoxin called oenanthetoxin, which triggers spasmodic convulsions, usually followed by sudden death.

Height: Tall and robust up to 1.5 metre.

Leaves: 3 to 4 either oval, lobed or toothed and in the same arrangement as a feather (pinnate).

The leaf stalk (petiole) is attached to the flower stem by a sheath.

Stems: Hairless, grooved and hollow.

Flowers are clustered in distinct umbels (they look like pom-poms).

Habitat: Found around lakes, marshy ground, ponds, along the waters-edge of rivers and river banks.

Flowers: Between May and August.

Lookalikes: Parsley (Petroselinum crispum), Wild celery (Apium graveolens), Narrow leaved water-parsnip (Berula erecta) and River Water-dropwort (Oenanthe fluviatilis).

It is a tuberous perennial plant that resembles celery with roots like a bunch of large white carrots.

The highest concentration of toxic properties is in the roots. Then the stems and finally the leaves.

The toxin seems able to enter the body through the skin, so care should be exercised when handling it, particularly any sap.

Be very careful when handling the leaves as there are reports that the toxin can enter the body through the skin. Be especially careful if you get sap on you.


  1. I saw this growing at the edge of the canal and thought it was celery. I smelt it and brought some home to id. It wilted so got thrown in the bin and I forgot about it until I saw this just now. I am so glad I did! X

  2. Thankyou for sharing this. It has s beautiful leaf and tempting to pick. Good to share for families out on their walks.
    May I share to our community group please?

  3. This is really interesting. It is strange how many delicious plants and fungi have a poisonous twin …with Hemlock it seems to be triplets as this looks completely different to Hemlock per se which is finer and more feathery, it also has the round hollow stem but has the dark red blotches. They also achieve the same height but the flowers are slightly different.
    Thank you for the lovely words and poem. So true. Even now in lockdown things get hectic. Lovely to have time to sit and stare.

  4. Really clear and helpful. There is a lot of this growing along the river Frome to the west of Dorchester, glad I know what to look out for with my grandson.

  5. Hello thank you for the video it was most helpful. Please can I ask does hemlock have purple spots on the stalk, as I couldn’t see any on the video. Also I noticed the plant was being touched by a bare hand and it was mentioned but to touch it as the toxins can enter the skin, so I just wanted further clarification on this pls. Many thanks

  6. Thank you, really useful. Also another request here please for a video for Hemlock. I picked a bunch of sweet cicely the other week to eat, but read that some people have confused it with hemlock. I was 99.9% sure it was sweet cicely, but since I’ve never knowingly come across hemlock I couldn’t definately say it wasn’t hemlock and I didn’t think it was worth the risk! Not much room for error with the Apiaceae! Thanks again.

  7. I have loads of it blocking the river at the bottom of my garden. I have pulled it up over several years, is there a better more effective way of controlling it?

    • Hiya Phil I Did the same when i first identified it – physically pulling it out and tbh it was fairly easy to do. I wear long gloves and wash my hands and face when finished.
      My only problem was that in doing so i damaged the river bank. So now I tend to treat the first growth with weed killer and then pull what little remains.

  8. Thank you so much for the video. I was searching to find the difference between wild celery and hemlock water dropwort. Some years ago I tasted wild celery soup made from plants growing nearby by the side of a stream. The cook told me that you had to be careful not to get the two plants mixed up. I would like to try some wild celery again but now it looks as though it’s very difficult telling them apart. The plants by the stream have a very strong smell, of celery but more pungent. How easy is it to tell the plants apart?

  9. Hi, I’m working in a garden and they have quite a lot of hemlock water dropwort – it’s just over flowering and setting seed – what should I do with it? Do I need to get someone in to remove it – I’ve read you can’t burn it so where do you dispose of it if I was to dig it up? I don’t really want to go near it in all honesty but I’m a gardener so is it my job?? Thanks

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