Hemlock is flowering now. It’s a deadly poisonous species and its great claim to fame is that its juice killed Socrates in 399 BC. We’ll return to that topic later.
Conium maculatum L. by Franz Eugen Köhler in Köhler’s Medizinal-Pflanzen published first in 1887. Wikipedia, PublicDomain.
Hemlock is a member of the plant Family Apiaceae (formerly called the Umbelliferae), along with carrot, parsley, parsnip and hogweed. Members the family tend to be biennials, germinating in the late winter or spring of the first year, forming a rosette of leaves and developing a large tap root to store starch during the summer. When winter comes the leaves usually die down. In the warmth of spring the tap root sprouts, making very rapid growth from stored reserves to form a large flowering stem on which the inflorescences appear as umbrella-like structures called umbels. Pollination is usually ‘promiscuous’ as the flowers are open to all-comers, and the masses of flowers make a convenient landing ground for any flying insect. Then, once the seeds have been shed, the plant dies.
Hemlock growing with docks and other ruderal species on a rubbish dump by the A77, Bennane Head, Ayrshire in mid-June 2023. Size: stems are up to 200 cm, usually less. Photo: John Grace.
Many of this family contain strong-tasting and biologically-active chemicals as a defence against herbivores. Those we’ve covered before on this site are Carrot, Hogweed, Alexanders, Giant Hogweed , Hemlock Water Dropwort– if you missed them you can click on the blue links. A consequence of the strong family likenesses in the Apiaceae is that its members are often confused with each other. This can be fatal when much loved culinary members are confused with deadly poisonous relatives. For example, Hemlock is often mistaken for Parsley, and Hemlock’s roots look like badly-grown Parsnips. A useful key difference is that Hemlock has red/purple blotches on the stem and petioles, although sometimes these are not well developed (as in Köhler’s painting, above). The smell of its crushed leaves is described as ‘mousey’ (a characteristic unpleasant smell that remains in one’s memory).
Hemlock flowers. Left: arrangement of umbels, middle: one compound umbel viewed from above, right: compound umbel from below. Images: Chris Jeffree.
According to the BSBI’s Plant Atlas 2020 it can be found in wet places such as ditches and riverbanks, and also drier habitats, including rough grassland, waste ground, refuse tips and roadsides. It seems to like motorway verges, and I have seen it in public parkland. I believe the relevant authorities fail to recognise it, thinking it is Cow Parsley. If you live in Scotland you are more likely to see it in the east. It grows best on fertile soils, avoiding acidic conditions.
Red/purple blotches on the hairless stem (a diagnostic feature). The image on the left is Hemlock and the one on the right is Giant Hogweed (they both have red blotches). But Giant Hogweed is a much larger plant and its leaves are not finely divided. Photos: Chris Jeffree.
Hemlock is not considered to be a native species but an ‘archaeophyte’, introduced from mainland Europe in early times. How early? In Britain, remains of the plant turn up at many Anglo-Saxon excavations (Carruthers and Dowse 2019). In the absence of recorded history during the Dark Ages, it is tempting to speculate that the Romans first brought it to Britain, most likely as a poison for conveniently executing criminals.
Early-stage of fruits. They are 2.5-3.5 mm, ovoid, somewhat compressed. Photo: Chris Jeffree.
But does it have a ‘good side’? It was well known to Hildegard von Bingen, the twelfth Century Benedictine Abbess of the Rhineland who has been described as a “visionary, mystic, healer, linguist…and preacher” (Throop 1998). She tells us that the water from cooked Hemlock can help ease the wounds of people who are “badly stricken by spears and cudgels”. John Gerard describes it in his Herbal of 1597, and Culpepper (1789) says it “may be applied to inflammations, tumours, and swellings in any part of the body (save the privy parts)..” But the medicinal importance of hemlock is very limited because of the closeness between therapeutic and poisonous levels.
Detail of the hairless compound leaf. The leaves of cow parsley are similar, but somewhat hairy.
Image: Chris Jeffree.
The toxic effect on humans, cattle, sheep, goat, swine, rabbit, elk, birds and insects are described by Vetter (2004). Based on the case of Socrates as described by Plato they are: a rapid loss of power of the lower extremities, staggering and trembling; then total paralysis of the legs and arms followed by a loss of the power to chew and the pupils become fixed. Finally, death due to paralysis of respiration and asphyxia, but the intellect remains clear until death. There are also many modern reports in the form of medical case histories, usually of children who have ingested Hemlock. After hospitalisation they have recovered (perhaps many have died but those cases have not been published).
Socrates didn’t recover. He had been charged with corrupting the youth of Athens and not recognising the Gods of the time. The jurors recommended the death penalty by making him drink a cup of hemlock. For a scholarly account of the life of Socrates, you may click here.
Death of Socrates by Jacques-Louis David 1787. Socrates sits defiantly in the middle of the picture and the others are distraught because they would rather not see him die. But he will drink the Hemlock cup. Public Domain (wikipedia: Catharine Lorillard Wolfe Collection, Wolfe Fund, 1931)
Finally, we note that Hemlock was well-known to Shakespeare in the late 16th Century. He refers to it and several other species, presumably all fairly common and well-known to his Elizabethan audiences. In his play Henry V, written around 1599, the Duke of Burgundy bemoans that the ‘nurse of arts, plenties, and joyful births’ has forsaken France:
Conium maculatum, distribution in Britain and Ireland. From BSBI/Maps.
References
Carruthers WJ and Dowse KL (2019) A Review of Macroscopic Plant Remains from the Midland Counties. Historic England Research Report 47/2019.
Culpepper N (1789) The Complete Herbal. https://www.gutenberg.org/files/49513/49513-h/49513-h.htm.
Throop P (1998) Hildegard Von Bingen’s Physica. Inner Traditions/Bear & Company, Rochester.
Vetter J (2004) Poison hemlock (Conium maculatum L.) Food and Chemical Toxicology 42, 1373–1382.
©John Grace
Botany in Scotland 