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Annual · Caryophyllaceae

Corncockle

Agrostemma githago

In other languages: Bolderik (Nederlands) · Nielle des blés (Français)

Corncockle is an annual cornfield flower that has travelled with cereal crops since prehistoric times and so spread from the Mediterranean region across the whole of Europe. It once coloured wheat fields purple-pink, alongside poppies and cornflowers, but seed cleaning and weed control have almost wiped it out in the wild. The plant grows 60–90 cm tall, with thin, hairy stems and narrow, grey-green leaves. From June to August it bears open flowers 3–5 cm across in purple-pink, with dark lines running towards the centre and long, narrow sepals that stick out between the petals. Gardeners sow it in a wildflower meadow or field margin for bees and butterflies. Well-known selections are the paler, lilac-pink ‘Milas’ and the white, speckled ‘Ocean Pearls’.

Caution: The seeds are poisonous: they contain saponins that can cause serious poisoning if eaten. Keep children away from the ripe seed capsules, never use the seed in bird or chicken feed and do not let it get mixed into grain or fodder crops. Chickens, livestock and pets are also at risk.

Updated on 10 October 2026

Light
Full sun
warm and bright
Moisture
Dry to normal
no wet feet
Legal basis
Sand, loam or clay
any pH
Hardiness
down to -10 °C
protect in harsh winters
Size
0.8 m
tall, 0.3 m wide
Flowering
June–August

Key facts
Height	0.8 m
Native to Belgium	Yes
Good for bees, butterflies and birds	Yes, for bees and butterflies
Poisonous to people and pets	Yes, take care with children and pets
Flowering	June–August

Identify

Corncockle: how do you recognise it?

Habit: Upright annual of 60–90 cm, sparsely branched, with slender stems.
Leaves: Narrow, linear, opposite and grey-green, densely covered in soft hairs.
Flower: Open, with five petals, 3–5 cm across, purple-pink with dark lines towards the paler centre. The narrow sepals are longer than the petals and poke out between them like the points of a star.
Fruit: An egg-shaped capsule with black, warty seeds, ripe in August–September.
Roots: A taproot: the plant resents transplanting, so sow it where it is to flower.

Flowering: June–August · Sowing: March–April and September–October

In your garden

Why grow it?

Large purple-pink flowers from June to August, swaying gracefully on slender stems.
Bees, bumblebees and butterflies visit the flowers.
An old cornfield flower of our region, almost lost in the wild but kept alive in gardens.
Easy: sow directly on poor soil, with no fertiliser and little water.
Perfect in a wildflower meadow or field margin with poppies, cornflowers and chamomile.

Corncockle: where does it grow best?

Full sun: in shade the stems flop and it flowers poorly.
Poor to moderately fertile soil: sand, loam or clay, acid to chalky. On rich soil it grows too lush and falls over.
Dry to moderately moist; once rooted it copes well with drought.
Thin to 20–30 cm between plants, so they support each other without crowding.

Light: Sun
Soil type: Sand, loam or clay
Acidity: Not fussy
Moisture: Dry or normal
Size: 0.8 m tall, 0.3 m wide
Hardiness: Tolerates light frost (to -10 °C)

Goes well with

Corn poppy: The classic red cornfield flower, blooming at the same time and preferring the same poor soil.
Cornflower: Bright blue next to the purple-pink: together the picture of an old wheat field.
Corn marigold: Yellow daisies that cheerfully complete the field margin.
German chamomile: Small white, fragrant flowers as an airy filler.
Ornamental cereals: Barley or oats give support and a true cornfield feel.

Maintenance

Corncockle: when and how to plant it?

Sow in September–October for early, vigorous flowering, or in March–April for flowers later in summer.
Prepare a fine, weed-free seedbed; no manure or compost is needed.
Sow the fairly large seeds thinly, about 1 cm deep, broadcast or in small groups.
Firm the soil lightly and keep it moist until the seedlings appear, usually after two to three weeks.
Thin the seedlings to 20–30 cm.
Do not transplant: with its taproot it grows best where it was sown.

Care

Water: Only just after sowing and in prolonged drought; older plants manage perfectly well.
Feeding: Do not feed: fertiliser leads to floppy stems and fewer flowers.
Support: Sow it with cereals, cornflowers or other annuals so they hold each other up. In a windy spot a few twiggy sticks help.
Deadheading: Remove faded flowers to prolong flowering, or let them ripen if you want to collect seed.
Clearing: Pull up the plants once the seed has ripened and lightly cultivate the soil if you want it to self-seed.

Tip: Sow it with poppies and cornflowers on a patch of poor, freshly cultivated soil: without fertiliser the plants stay sturdier and flower more freely.

Corncockle: when to prune it?

When: Corncockle is not pruned. As an annual, it is cleared away after flowering and seed ripening.

How:

Snip off faded flowers if you want to extend flowering a little.
Let some of the flowers set seed if you want to sow again next year.
Pull up the dead plants in September or cut the field margin then.

Caution: Do not let seed end up in the vegetable garden or among edible crops: the seed is poisonous.

Pruning calendar and basic rules

Propagation

Seed: The only method. Collect the capsules in August–September when brown and dry, let them finish drying and store the seed cool, dry and clearly labelled, out of reach of children. Sow it in place in autumn or spring.
Self-seeding: It only self-seeds on cultivated, open ground. Lightly rake or hoe the spot in autumn and new seedlings will appear.

Corncockle: how does it get through the winter?

Hardy to −10 °C: protect in harsh winters.

Autumn sowings overwinter as small rosettes and tolerate frost to about −10 °C; in a harsh winter some plants may be lost.
If you want no risk, sow (as well) in March–April.
The plant dies once the seed has ripened; only the seed survives the winter.

Diseases and pests

Flopping: Tall plants fall over after wind or rain, especially on rich soil. Sow more densely with other cornfield flowers and do not feed.
Aphids: On shoot tips and buds. Ladybirds and hoverflies usually clear them up; otherwise hose them off with water.
Slugs: They eat young seedlings. Sow a little more thickly and pick slugs off in the evening.
No seedlings: On undisturbed soil or in dense grass the seed does not germinate. Lightly cultivate the soil in autumn or sow again yourself.

Through the year

March: Sow in place in a fine seedbed.
April: Sow. Thin autumn sowings to 20–30 cm.
May: Thin spring sowings. Weed.
June: Flowering begins. Bees and butterflies visit.
July: Full flower. Remove faded flowers if you like.
August: Last flowers. Let seed ripen and collect it.
September: Collect and store seed. Clear faded plants. Sow for next year.
October: Sow in place. Lightly cultivate the soil where it may self-seed.

Use

Edible and useful

Not edible. The seeds of corncockle are poisonous: they contain saponins (githagin), which cause vomiting, stomach ache, diarrhoea and, in larger amounts, serious poisoning if swallowed. In the past, when corncockle grew among the corn, flour containing its seeds made people and animals ill. So never use corncockle seed in bird or chicken feed, do not let it get mixed into grain or fodder crops, and take care with packets of wildflower mix that contain it. Keep children away from the ripe seed capsules; chickens, livestock and pets are at risk too. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Good for wildlife

Bees: Nectar and pollen for honeybees and wild bees.
Butterflies: Nectar for butterflies.

You and this species

Did you know?

With old methods its seeds were hard to separate from the grain. So for centuries the plant travelled with the harvest and sometimes ended up in flour.
The long sepals sticking out between the petals are a good way to recognise it.
In the twentieth century it vanished from almost all fields thanks to better seed cleaning and weed control.

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