Alexanders
  Alexanders
Bird's-Nest Orchid
  Bird's-Nest Orchid
Common Wintercress
  Common Wintercress
Black Medick
  Black Medick
Blue Bugle
  Blue Bugle
English Bluebell
  English Bluebell
Bulbous Buttercup
  Bulbous Buttercup
Bush Vetch
  Bush Vetch
Chalk Milkwort
  Chalk Milkwort
Common Chickweed
  Common Chickweed
Cleavers
  Cleavers
Coltsfoot
  Coltsfoot
Common Broom
  Common Broom
Common Cornsalad
  Common Cornsalad
Common Fiddleneck
  Common Fiddleneck
Mouse-Ear Chickweed
  Mouse-Ear Chickweed
Common Storksbill
  Common Storksbill
Wall Speedwell
  Wall Speedwell
Cow Parsley
  Cow Parsley
Cowslip
  Cowslip
Common Crosswort
  Common Crosswort
Cypress Spurge
  Cypress Spurge
Daffodil
  Daffodil
Common Daisy
  Common Daisy
Common Dandelion
  Common Dandelion
Dog's Mercury
  Dog's Mercury
Dove's-Foot Cranesbill
  Dove's-Foot Cranesbill
Early Crocus
  Early Crocus
Wood Forget-Me-Not
  Wood Forget-Me-Not
Garlic Mustard
  Garlic Mustard
Germander Speedwell
  Germander Speedwell
Common Gorse
  Common Gorse
Garden Grape-Hyacinth
  Garden Grape-Hyacinth
Greater Celandine
  Greater Celandine
Greater Periwinkle
  Greater Periwinkle
Greater Stitchwort
  Greater Stitchwort
Green Alkanet
  Green Alkanet
Ground Ivy
  Ground Ivy
Common Groundsel
  Common Groundsel
Common Hedge Mustard
  Common Hedge Mustard
Hemlock Water Dropwort
  Hemlock Water Dropwort
Herb Robert
  Herb Robert
Honesty
  Honesty
Ivy-Leaved Toadflax
  Ivy-Leaved Toadflax
Ivy-Leaved Speedwell
  Ivy-Leaved Speedwell
Cuckooflower
  Cuckooflower
Lesser Celandine
  Lesser Celandine
Lesser Periwinkle
  Lesser Periwinkle
Marsh Marigold
  Marsh Marigold
Meadow Buttercup
  Meadow Buttercup
Meadow Saxifrage
  Meadow Saxifrage
Oregon Grape
  Oregon Grape
Oxford Ragwort
  Oxford Ragwort
Pheasant's Eye Narcissus
  Pheasant's Eye Narcissus
Pink Purslane
  Pink Purslane
Common Primrose
  Common Primrose
Ramsons
  Ramsons
Red Dead-Nettle
  Red Dead-Nettle
Red Valerian
  Red Valerian
Ribwort Plantain
  Ribwort Plantain
Round-Leaved Cranesbill
  Round-Leaved Cranesbill
Rue-Leaved Saxifrage
  Rue-Leaved Saxifrage
Sheep's Sorrel
  Sheep's Sorrel
Shepherd's Purse
  Shepherd's Purse
Smooth Sow Thistle
  Smooth Sow Thistle
Spring Crocus
  Spring Crocus
Stinking Hellebore
  Stinking Hellebore
Sweet Violet
  Sweet Violet
Sweet Woodruff
  Sweet Woodruff
Thyme-Leaved Speedwell
  Thyme-Leaved Speedwell
Common Dog Violet
  Common Dog Violet
Wallflower
  Wallflower
Wavy Bittercress
  Wavy Bittercress
White Comfrey
  White Comfrey
White Dead-Nettle
  White Dead-Nettle
Wild Arum
  Wild Arum
Woodland Strawberry
  Woodland Strawberry
Winter Purslane
  Winter Purslane
Wood Anemone
  Wood Anemone
Common Wood Sorrel
  Common Wood Sorrel
Wood Speedwell
  Wood Speedwell
Yellow Archangel
  Yellow Archangel
Yellow Crocus
  Yellow Crocus
Hairy Bittercress
  Hairy Bittercress
Petty Spurge
  Petty Spurge
Common Whitlowgrass
  Common Whitlowgrass
Sweet Violet (White)
  Sweet Violet (White)
Field Speedwell
  Field Speedwell
Sea Thrift
  Sea Thrift
Spanish Bluebell
  Spanish Bluebell
Moschatel
  Moschatel
Summer Snowflake
  Summer Snowflake
Sun Spurge
  Sun Spurge
Early Purple Orchid
  Early Purple Orchid
Early Forget-Me-Not
  Early Forget-Me-Not
Wood Spurge
  Wood Spurge
Spring Squill
  Spring Squill
Sea Campion
  Sea Campion
Sticky Storksbill
  Sticky Storksbill
Filters:

Poison Hemlock Conium maculatum 

 
 
Attracts BeesBees are attracted to this plant
Attracts ButterfliesButterflies are attracted to this plant
Biennial Life CycleBiennial life cycle
Umbrella-Shaped FlowersUmbrella-shaped flowers
White FlowersWhite flowers
5 Petals5 petals
Jun-Jul Flowering
period
Pinnate LeavesPinnate leaves
Lobe-Edged LeavesLobe-edged leaves
Ribbed StemRibbed stem
Tap RootTap root
200cmMaximum height
 
 
  Main image of Poison Hemlock
© 2021 Adrian Briggs
 

Poison Hemlock is a non-native biennial plant of the UK, typically found growing in grassland, hedgerows and waste ground, to a mature height of up to 200cm.

Poison Hemlock is one of the most deadly plants to be found growing wild in the UK. It is also very common, found widely distributed across the UK. Even the ingestion of small amounts of any part of the plant, or skin absorption of the sap, can cause severe poisoning to humans and livestock. Poison Hemlock contains the toxic alkaloid Coniine and symptoms of poisoning include: gastrointestinal problems; irregular heartbeat; seizures and paralysis; respiratory failure; and death. Unfortunately there is no specific antidote to this toxin and so extreme care needs to be taken to avoid contact with the plant. Please see the notes below under 'Concerns' for details of plant identification.

Botanic classification and naming: Poison Hemlock is a member of the Carrot (Apiaceae) family. The genus name 'Conium' identifies the plant as a Poison Hemlock and its species name 'maculatum' means 'spotted (stems)'.

Concerns: All parts of Poison Hemlock are deadly toxic and unfortunately the plant leaves and white umbel flowers looks similar to several other members of the Carrot family, including Cow Parsley, Wild Carrot, Upright Hedge Parsley and Bur Chervil. Hemlock has been mistaken for Cow Parsley and Wild Carrot by foragers with fatal consequences. Accidental misidentification is all the more likely because both Poison Hemlock and Cow Parsley can be found growing close together. In view of this, foraging for members of the Carrot family is inadvisable and very strongly discouraged. However, it is important to be able to identify Poison Hemlock, to avoid any contact with the plant. Characteristics of Poison Hemlock to note include: a smooth and slightly-ribbed main stem; distinctive purple blotches on the stems (but these may be absent in young plants); rounded and hollow side branches; feathery leaves (finely divided between 2-4 times); and the plant is said to have an unpleasant mousy odour.

Benefits: Poison Hemlock is pollinated by bees and butterflies. It also provides a food source for moth caterpillars, such as those of the Poison Hemlock moth and Silver Ground Carpet moth.

Benefits to wildlife are also indicated with orange icons in the plant profile bar at the top.

 

 
Flower of Poison Hemlock

© 2021 Adrian Briggs

 

Flowers:
Poison Hemlock usually flowers between June and July.

Flower colour:

Flower Colour White

White

Flower shape:

Flower Shape  Umbrella

Umbrella

Petals:

Petal Number =  5

5

Leaf of Poison Hemlock

© 2021 Adrian Briggs

 

Leaves:

Leaf Shape:

Leaf Shape is Pinnate

Pinnate

Or:

Alternative Leaf Shape is Divided

Divided

Leaf Margins:

Leaf Margin is lobed

lobed

Stem of Poison Hemlock

© 2021 Adrian Briggs

 

Stem and Roots:

Stem shape:

Stem Shape is Ribbed

Ribbed

Root type:

Root Type is Tap

Tap