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Herbaceous PerennialBogs

Oenanthe crocata

hemlock water dropwort

Hemlock water dropwort is an extremely poisonous, perennial plant. It forms elongated root tubers and has erect, hollow, grooved stems. Leaves are pinnate and flowerheads of white umbels, 5-10cm across, are borne in July and August

Other common names
balder root
ban dock
see moredead tongue
hemlock dropwort
hemlock wort
water hemlock
Size
Ultimate height
1–1.5 metres
Time to ultimate height
2–5 years
Ultimate spread
1.5–2.5 metres
Growing conditions
Clay
Loam
Moisture
Poorly–drained
pH
Acid, Alkaline, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Green
Summer White Green
Autumn Green
Winter
Position
  • Full sun
Aspect

East–facing or South–facing or West–facing

Exposure
Sheltered
Hardiness
H7
Botanical details
Family
Apiaceae
Native to the UK
Yes
Foliage
Deciduous
Habit
Clump forming
Potentially harmful
TOXIC if eaten. Wear gloves and other protective equipment when handling TOXIC to pets if eaten (dogs) - see the HTA guide to potentially harmful plants for further information and useful contact numbers
Genus

Oenanthe are perennials with a preference for damp ground, marshes or water. Hollow stems are shiny and can grow up to 2m tall. Leaves are triangular, shiny and bright green and flowers are arranged in small white clusters. Brown, rugby-shaped seeds follow the flowers.

Name status

Correct

Plant range
Europe, N. Africa

How to grow

Cultivation

Hemlock water dropwort grows naturally in damp meadows and near ditches and ponds and can become a nuisance if left unchecked. For a list of alterntive plant to use in ponds and streams, please go to our advice profile on pond plants

Propagation

Propagate by seed

Suggested planting locations and garden types
  • Wildlife gardens
Pruning

No pruning required

Pests

Generally pest-free

Diseases

Generally disease-free

Get involved

The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.