Water hemlock
Cicuta virosa · Apiaceae
Water hemlock is a highly toxic plant from the Apiaceae family, naturally found in wet and marshy areas across temperate Europe and Asia. Its tall, hollow stems with distinctive reddish-purple blotches and finely divided, triangular foliage make it recognizable in damp habitats. Despite its toxicity, it can be cultivated as a botanical specimen in controlled garden settings, provided you take appropriate safety precautions and keep it away from children and pets.
The gardener's calendar
Ideal time to plant water hemlock: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Foliage
- Deciduous
- Flowering
- July to September
- Mature size
- 60 to 120 cm in height
- Growth
- Fast
- Hardiness
- Hardy, down to -15°C
- Origin
- Temperate Europe and Asia
- Soil type
- Moist, marshy, rich in organic matter
- Natural habitat
- Wet zones, ditches, riverbanks
Care
Watering
Water hemlock demands constant soil moisture, even regular waterlogging. Keep your substrate very wet, especially during the growing season. In nature, it thrives at the water's edge or in flood-prone areas.
Light exposure
Choose a sunny to partially shaded spot. The plant tolerates direct light well and produces more vigorous growth with at least 4 to 6 hours of daily sun.
Soil
Look for moist soil rich in organic matter and slightly acidic. A substrate made of peat, compost, and draining sand, without excess lime, works best. Adding compost improves structure.
Fertilizing
A moderate application of balanced fertilizer in spring and early summer is sufficient. Avoid over-fertilizing, which would push excessive growth at the expense of plant structure.
Pruning and training
No strict pruning is necessary. You can remove faded stems in late autumn or early spring. The plant naturally develops as a branched clump.
Diseases and pests
Water hemlock is generally little affected by diseases when grown in appropriate moist conditions. Watch for rot if water stagnates for extended periods or if humidity is excessive without adequate air circulation.
Did you know?
Water hemlock is one of Europe's most toxic plants: all its parts, especially the tuberous roots resembling small turnips, contain formidable neurotoxic alkaloids. It has often been confused historically with other edible umbellifers, leading to accidental poisonings. Its name 'virosa' literally means 'toxic' in Latin.
Where to buy it
Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.
Add this plant to my garden →Plants from the same family
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- Shrubby Hare's EarBupleurum fruticosum
- Crowfoot-leaved hare's-earBupleurum ranunculoides
Tips generated and checked by Viridia — adapt them to your local climate.