Henbane

How to recognise it

Habit

Upright, sparsely branched plant of 30–80 cm, annual or biennial; biennial plants first form a large leaf rosette.

Leaf

Greyish-green, large and soft, coarsely toothed to deeply cut, sticky-hairy and foul-smelling; the stem leaves clasp the stem.

Flower

Funnel-shaped, 2–3 cm, dull creamy yellow with a dense net of purple veins and a dark purple centre, in one-sided spikes in the leaf axils, from June to September.

Fruit/Seed

Capsule with a lid, hidden in the enlarged, urn-shaped calyx with five stiff points; it holds hundreds of small, greyish-brown seeds.

Stem

Thick, sticky and densely hairy.

Confused with

Thorn-apple has large white trumpet flowers and a spiny capsule, and is also highly poisonous. Other nightshades, such as bittersweet and black nightshade, have small star-shaped flowers. A young rosette can look like an edible leaf: never eat plants you are not sure of.

Flowering: June–September · Pruning: August–September

Why grow it?

• Strikingly patterned flowers: dull yellow with a network of purple veins, a real eye-catcher.
• Bumblebees and other bees visit the flowers for nectar and pollen.
• A rare plant of old farmyards, dunes and rough ground: coming across it is a special experience.
• Historically interesting: it is one of the best-known poisonous plants in history and folklore.
• The urn-shaped fruiting calyces make a striking dry structure in autumn.

Henbane: where does it grow best?

• In the wild: open, fertile, disturbed ground such as farmyards, muck heaps, rough ground, waste land, field edges, dykes and rabbit-grazed dunes.
• Full sun and warm, open sites.
• Dry to moderately moist, nitrogen-rich, sandy or limy soil.
• In the garden: only in a fenced-off corner of a historical or educational herb garden, never where children play or pets roam.

Goes well with

• Great mullein: Tall yellow spikes on the same warm, dry soil.
• Viper’s bugloss: Blue flowers for bumblebees on sunny rough ground.
• Wild mignonette: Pale yellow spikes, another plant of disturbed, limy ground.
• Feverfew: Another old herb-garden plant, with small white daisy-like flowers.

Henbane: when and how to plant it?

1. First ask yourself whether you really want it: never grow it in a garden with young children or pets, or next to a field with grazing animals.
2. Buy seed from a supplier of wild or heritage plants; never dig up plants from the wild.
3. Sow in September–October or March–April on an open, sunny spot and cover the seed only very lightly.
4. Thin the seedlings to 40–50 cm, wearing gloves.
5. Put a clear label or a low fence around the spot so that nobody eats it or collects the seed.
6. Water only until germination; after that no watering is needed.

Care

Water

Not needed; it likes dry, warm spots.

Feeding

Not needed.

Gloves

Always wear gloves when you touch the plant, wash your hands afterwards and do not rub your eyes.

Letting it seed

The seed stays viable in the soil for many years. Cut off the fruits before they ripen if you do not want it to self-sow.

Disposal

Put dead plants with fruits in the green waste bin or the general waste, not on your own compost heap.

Tip: If you want to show henbane in an educational herb garden, grow it behind a low fence with a clear ‘poisonous’ sign.

Pruning and mowing

Pruning months: August–September.

When: In August–September, before the fruits ripen.

How:

• Wear gloves and long sleeves.
• Cut off the stems with fruiting calyces before they turn brown, if you do not want seedlings.
• If you let one plant ripen for seed, cut it in good time and store the seed out of children’s reach.
• Dispose of the cuttings in the green waste bin or the general waste, not on your own compost heap.

Caution: Wash your hands thoroughly after the job and do not rub your eyes: all parts of the plant are poisonous.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Ripens from August in the urn-shaped calyces. Sow in autumn or spring; germination is erratic, sometimes only after a year or more.

Henbane: how does it get through the winter?

Hardy to −20 °C.

• Annual plants die in autumn; the dry stems with urn-shaped fruiting calyces remain standing.
• Biennial plants overwinter as a leaf rosette and flower the following year.
• The rosettes are hardy to about −20 °C.
• The seed survives in the soil for many years and often only germinates when the ground is disturbed.

Diseases and pests

• Poisoning: The biggest risk. Keep it out of reach of children and animals, label the plant and wear gloves.
• Unexpected reappearance: It can come up again years later. Pull out unknown seedlings, wearing gloves, before they flower.
• Flea beetles: Tiny jumping beetles chew small holes in the leaves. Usually not serious; just let it be.
• Disappearing: Where the ground is no longer disturbed, it vanishes after a few years. Lightly loosen the soil now and then.

Through the year

• March: Sow on an open, sunny spot, wearing gloves.
• April: Thin seedlings to 40–50 cm.
• May: Biennial rosettes start to flower.
• June: First purple-veined flowers.
• July: Full flower; bumblebees visit the flowers.
• August: Fruiting calyces swell; cut them off if you do not want seed.
• September: Last flowers. Sow for biennial plants.
• October: Clear dead plants, wearing gloves.

Did you know?

• Hyoscyamus comes from the Greek hys, pig, and kyamos, bean: ‘hog’s bean’. The English name henbane means ‘death of hens’ and points to its poison.
• In old folk tales henbane is one of the ingredients of so-called witches’ ointments and magic potions.
• The seed can survive in the soil for a very long time: henbane sometimes appears suddenly where old ground is disturbed, for example during building work or archaeological digs.