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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

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Ultimate height

1–1.5 metres

Time to ultimate height

2–5 years

Ultimate spread

1.5–2.5 metres

Clay

Loam

Moisture

Poorly–drained

pH

Acid, Alkaline, Neutral

	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Full sun

Aspect

East–facing or South–facing or West–facing

Exposure

Sheltered

Hardiness
Hardiness ratings
All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets
H1a: under glass all year (>15C)
H1b: can be grown outside in the summer (10 - 15)
H1c: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20)

Botanical details

Family: Apiaceae
Native to GB / Ireland: 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

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