Poisonous Poisonous Spring Spring Summer Summer

A common deadly poisonous plant from the Apiaceae or Umbellifer family that will tolerate many different environments and conditions.

Hedgerow Type
Common Names Hemlock, Poison Parsley
Scientific Name Conium maculatum
Season Start Mar
Season End Sep
Please note that each and every hedgerow item you come across may vary in appearance to these photos.


A bit fern like with two to four pinnate divisions, the whole looking triangular in shape.


A white collection of tiny flowers growing in an umbel in Spring to early Summer.


Small flat green seeds that brown on maturity.


The stem is smooth, hairless, grooved, green and usually covered in purple/red spots and streaks and can reach up to eight feet tall.


Like a parsnip only usually more twisted and forked.


Roadsides, waste ground, field edges, path edges, meadows, and poorly drained soil near streams or ditches.

Possible Confusion

With its purple spots and unpleasant smell it is hard to confuse this plant with any other than Chervil, pictured, or other Umbellifers, some of which are deadly poisonous..


Unpleasant, said to be like mouse urine or off parsnips.



Medicinal Uses

It was used in the past as a sedative and antispasmodic but is considered too toxic for home medicinal use now.

Other Facts

This member of the Apiaceae or Umbellifer family is acutely toxic to people and animals and symptoms can appear twenty minutes to three hours after ingestion. All parts of the plant are poisonous and even the dead canes remain toxic for up to three years. It doesn’t just have to be eaten to poison people, it has been reported that touching the plant for lengths of time, when pulling up large stands of Hemlock without gloves, has allowed the toxin to penetrate through the skin and make the person involved very ill.
It was used as a form of execution in ancient Greece and Socrates chose it as his form of execution and talked about his experience as it took hold. It numbed him from the toes and fingers up until reaching his heart and lungs and killing him.
Hemlock is the tallest native Umbellifer in the UK.


5 comments for Hemlock

  1. Ashok Jethwa says:

    One of the best sites for a beginner forager-both for the descriptions and videos too!

  2. Tim says:

    It should really have been mentioned that the roots of Hemlock are by far the most toxic part of Oenanthe crocata.

  3. Lionel Stanbrook says:

    I had a near miss with this quite recently. I had been reading on the subject and went out to find some and compare it with cow’s parsley. I found both but I think I was infected by just touching and examining (including breaking the stem) the poisonous plant too much and initially had symptoms of dizziness. The next morning I woke with an acute stomach cramp which worsened through the morning but subsided later in the day. I went out in the evening and found that my resistance was very low and I shivered my way through an open air dinner, needing to get back to warmth very quickly. Nothing has happened since then (about four days ago) although I need to know if I have done any lasting damage to myself! I found the hemlock growing profusely by the roadsides and especially in the wooded areas of Streat, near Plumpton in East Sussex. Some of it growing very thickly in the woods and already growing high up to a metre, especially where there is also bluebell and wild garlic. Has anyone else noticed that there is a lot more of it growing in southern England rural areas right now than ever before?

    1. Eric Biggane says:

      I’m not doubting your symptoms but touching hemlock and getting the sap on your hands is unlikely to cause any harm. Touching any poisonous plant or mushroom in the UK will not cause poisoning unless ingested. There are however plants that can cause severe reactions to the skin and although this is very unpleasant, it will not poison you.

  4. Emily Fox says:

    There is a noticeable increase in stands of it this year in Cambridgeshire too. Also of ragwort. So probably not a localised phenomenon but perhaps seasonal climatic specifics this year.

    Also getting sap on your skin would allow it to penetrate into the blood stream as the human skin is porous (which is another reason to wash your hands).

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