No, it is a hardy annual that completes its life cycle in one season.

Does it need full sun?

Yes, it performs best in full sun for the most prolific flowering.

Plant guide

Corn Cockle.

Agrostemma githago

Pronounced a-gro-STEM-uh GITH-uh-go

Also known as Common corncockle, Corncockle, Purple cockle

The corn cockle is a charming, old fashioned wildflower that adds a touch of rustic beauty to any garden. It produces lovely, trumpet shaped flowers in shades of pink and purple. These annuals are quite easy to grow from seed and attract plenty of pollinators.

Another photo of Corn Cockle — Photo by zebedeugalinha (CC BY) via iNaturalist

At a glance

Care level: Easy
Plant type: Annual wildflower
Light: Full sun
Indoor light: Direct sun
Water: Every 3 to 7 days
Mature size: 3 feet
Growth rate: Fast
Hardiness: USDA 3 to 9
Bloom time: Late spring to mid summer

Care

Sow seeds directly into the garden in autumn or early spring where they will receive plenty of sun. Keep an eye out for aphids or mildew if the weather stays damp for too long. Deadhead spent blooms if you want to prevent them from self seeding throughout your beds.

Watering: Water when the top inch of soil feels dry to the touch.
Feeding: These plants generally do not require supplemental fertilizer if grown in decent garden soil.
Pruning: Remove faded flowers to keep the plant tidy and encourage more blooms.
Repotting: As an annual, this plant completes its life cycle in one season and does not require repotting.
Soil: Well draining, loamy soil
Soil pH: 6.0 to 7.5
Temperature: -20 to 30°C
Humidity: 40 to 70%
Drought tolerance: Moderate
Lifespan: Annual, one season
Deer and rabbits: Moderate

Signs it needs repotting

Roots growing out of the drainage holes.
Stunted growth despite regular watering.

Safety

People: The plant contains saponins that cause severe gastrointestinal distress if eaten.
Pets: This plant is toxic to cats and dogs if ingested, as it contains saponins that can cause digestive distress.
Children: Keep this plant away from children as the seeds are highly toxic if swallowed.
Contact allergens: The foliage can cause mild skin irritation in sensitive individuals.
Airborne allergens: The pollen may trigger mild allergic reactions in sensitive people.
Edibility: All parts of this plant are toxic if ingested and should never be consumed.

How to identify it

Slender, hairy, upright stems
Narrow, linear, opposite leaves
Showy, five petaled pink flowers
Dark purple lines on petals
Large, papery, persistent calyx lobes

Height: 0.3 to 0.9m
Spread: 0.15 to 0.3m
Leaves: green, deciduous
Flowers: pink, purple, 3 to 5cm
Fruit: black, Late summer

Problems to watch for

AphidsCommon
Powdery MildewCommon
Root RotUncommon
Slugs and SnailsUncommon

By symptom

Plant problems by symptom

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Growing it

Propagation: seed
When to plant: spring, autumn
Overwintering: In mild climates, sow seeds in autumn to overwinter as small rosettes. In colder regions, it is best to sow in early spring after the threat of frost has passed.
In containers: It can be grown in containers, but it is best suited for open garden beds where it can self seed.

Seed

1. Collect seeds from dried pods in late summer.
2. Direct sow seeds into prepared soil in autumn or early spring.
3. Cover with about 1 cm of soil, as the seeds germinate best in darkness.
4. Thin seedlings to 15 centimeters apart.
5. Keep the soil moist until established.

Sow these in autumn for an early display in spring as they appreciate the cool start.

Grows well with

Cornflower · They share similar growing requirements and create a classic meadow aesthetic.
California Poppy · These provide a nice color contrast and thrive in similar sunny conditions.

Similar species

Red Campion · Both belong to the Caryophyllaceae family and share similar flower structures.

Science

Family: Caryophyllaceae
Genus: Agrostemma
Order: Caryophyllales
Class: Magnoliopsida
Native range: Europe and Western Asia.
Conservation: It is considered a vulnerable or endangered species in several European countries due to agricultural intensification.

It thrives in disturbed soils and open fields where it can compete for light with other annuals.

Value to wildlife: nectar source
Pollinators: bees, butterflies
Uses: cottage gardens, meadow plantings, cut flowers

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 1/9
Soil reaction: 6/9
Light: 8/9
Temperature: 5/9
Moisture: 4/9
Nutrients: 5/9

Taxonomy resolved against GBIF.

Questions people ask

Is it a perennial?: No, it is a hardy annual that completes its life cycle in one season.
Does it need full sun?: Yes, it performs best in full sun for the most prolific flowering.

Where the name comes from

The genus name Agrostemma comes from the Greek words for field and garland, while githago refers to the black seeds.

Good to know

It was historically known as corn cockle because it grew among corn crops.
The seeds are about the same size as wheat grains, which historically made them difficult to separate during harvest.
It is an annual that readily self seeds in the garden.

Also in

Plants toxic to cats and dogs

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This guide was generated with AI on September 26, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.