Poisonous Plants -3   The hemlock water dropwort.

Hemlock water dropwort--Oneanthe crocata

This is the third in the series poisonous plants See associated pages below. 

Another member of the---

This species is another member of the Apiaceae family which includes many species used by us for culinary or medicinal purposes, such as parsley, celery and fennel. In poisonous plants -2 I reviewed the notorious hemlock for its poisonous traits, however, this commoner species is probably more poisonous than hemlock and far more deadly for it is more easily mistaken for other harmless members of the family.

When the Irish lads were over digging out our canal systems fatalities occurred when the stems of the hemlock water dropwort were eaten in mistake for wild celery, an easy mistake to make. As I have stressed many times when writing about this family of plants, correct identification is essential. In many communities there will be someone with knowledge of this family of plants, who is available to help identify them. many regions will have organisations such as the Countryside rangers Service and Wildlife Trusts who organise wild flower walks led by experts. Only experience will help the forager to correctly identify these poisonous plants.

Foliage and flower buds of hemlock water dropwort.

photograph by Dal

Description of the hemlock water dropwort.

The roots of Oneanthe crocata are perennial and fleshy of a pale yellow colour when cleaned. The taste is said to be sweet then bitter, but not unpleasant {another reason they are mistakenly eaten., but has we have seen is deadly poisonous.

Because they grow in the margins of ponds lakes and ditches, the roots are sometimes exposed by running water. This makes them tempting to cattle and many cases of poisoning have been recorded due to them grazing on these roots. The roots are tuberous and not unlike the tubers of the garden dahlia in form while those of the related water parsnip are conical in outline.

The stems of this tall plant, and indeed the foliage, are superficially similar to those of the celery. The stems are thick and erect and much branched above. They are tough and dark green. 

Foliage and umbels of the hemlock water dropwort--photograph by Dal

The foliage can also have  a deceiving resemblance to the leaves of celery, however, the leaf segments can vary somewhat in form. The lower leaves are have short stalks that have a sheath [a characteristic of this family] ,where the leaf stalk meets the main stem.

The leaves are quite large and spreading in habit of ten reaching 30cm {one foot } long. The leaf as a whole is triangular in outline as the photograph above demonstrates. The leaf is much divided, the leaflets being diamond to wedge shaped. They are each one to one and a half inches long {2+cm}. They have deeply irregular lobes, dark green above paler and more shiny below.

The upper leaves are much smaller and almost stalk-less. The segments narrow and acute. 

The flower umbels of hemlock water dropwort--Below the seed capsules {fruits} forming.

photograph by Dal

The flowers

The flowers of hemlock water dropwort are borne in large umbels  {think umbrella} with many strong rays {spokes}. They are from 5-10cm wide. They may be encountered from June until the end of July. The flowers are white. The umbels  are made up of many small individual flowers. 

These are succeeded by the fruits {seed capsules}  Pictured above. Each are 4-6mm long. 


The hemlock water dropwort contains Oenanthe toxin. The stem and especially the roots are very poisonous. One root is sufficient to kill a cow. Human fatalities are not uncommon.

hemlock water dropwort is a very common plant that needs to be treated with the utmost respect and must never be used for human consumption. 

SIMILAR PLANTS.--- Angelica. and water dropwort. many of the this family have similar traits.

The celery like stems of hemlock water dropwort

Photograph by Dal.

Reuse of images. 

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Poisonous plants-1--{Foxglove}
Poisonous plants--2 { Hemlock}
Cow parsley
Wild herb advise.