Hemlock Water Dropwort (Oenanthe crocata) FAQs

Frequently asked questions about Hemlock Water Dropwort for a UK resident:

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Hemlock Water Dropwort (Oenanthe crocata) FAQs

Probably the most poisonous plant in the UK.

Hemlock Water Dropwort
Hemlock Water Dropwort
Hemlock Water Dropwort

Common names include Hemlock Water Dropwort, Water Hemlock, Dead Man's Fingers, and Dead Tongue.

The scientific name is Oenanthe crocata.

Yes. Hemlock Water Dropwort is probably the most poisonous plant in the UK and is toxic to both humans and livestock.

No. Hemlock Water Dropwort is not listed as a non-native invasive plant, but once established can become very invasive.

Hemlock Water Dropwort typically flowers from June to July.

Hemlock Water Dropwort is part of the Umbellifer (Carrot) family and so typically has small white flowers growing in umbrella-shaped clusters. Identification cues include bright green, shiny, fern-like leaves, which can look a bit like parsley. Stems are bright green, hollow, grooved, hairless, and can look a bit like celery.

In the Winter Hemlock Water Dropwort is one of the few active plants and so can be a good time to identify it.

It grows in damp areas like marshes, along lakes, rivers, streams, and ditches. Plants may occur several metres inland from the water's edge.

It may be confused with flat-leaved parsley, water parsnip, or water celery.

No, being probably the most poisonous plant in the UK, Hemlock Water Dropwort is not used medicinally

All parts of the Hemlock Water Dropwort plant, including the stems, leaves, roots, and seeds contain extremely toxic compounds that can cause death within hours of ingestion. The toxins act by constricting muscles leading to asphyxiation.

Plants can grow 1 to 1.5 metres tall, reaching their full height in 2 to 5 years. At maturity, they can spread 1.5 to 2.5 metres wide.

As a perennial, established plants grow back year after year. It also spreads by seeds which develop after flowering. Both mechanisms allow it to proliferate, especially in damp areas.

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Hemlock Water Dropwort