Agrostemma Plant Growing & Care Guide for Gardeners

Article by Dean Ravenscroft, Ph.D. - Updated 18th Oct 2023

In this Gardener's HQ guide, we'll explore cultivating Agrostemma plants in your garden, indoor spaces, and other settings.

Corn Cockle: Cultivation & Garden Use

The common name for the Hardy annual Agrostemma plant is the Corn cockle.

It typically flowers in the summer.

Description of Agrostemma

Agrostemma are medium sizes plants that can grow to between 60 and 90 cm (2 to 3 feet) in height. Agrostemma has very small trumpet shaped dark pink flowers.

It is an ideal plant for growing in borders and cottage gardens.

How to Grow Agrostemma

It is best to sow Corncockle at a depth of 1/8th inch (1/4 cm), with a spacing of nine to 12 inches (22 to 30 cm). Sow in early spring after the last frost as occurred. The Agrostemma plant prefers to grow in full sunlight.

The soil should ideally be a rich loam, though the plant is capable of surviving in most soils.

Agrostemma requires between two or three weeks for germination to occur.

If initiating growth indoors, then it is best to sow at a temperature of 55 to 64°F (13 to 18°C). Do so about seven or eight weeks before planting outdoors in the early spring or late autumn in milder climates.

Taking care of corn cockle in the garden

Corn cockle is easy to take care of, it requires watering in dry spells during the summer. Remove spent flower heads to stop seed set, and to prevent seed-set and the risk of the plant becoming a weed. The seeds of the plant are poisonous so use gloves and handle with care.

Information on Agrostemma and Commonly Grown Garden Species

The Agrostemma genus usually consists of just two main species (with some classificaions having it include 15 species) and is a member of the Caryophyllaceae family.

This large family contains 42 genera including Carnations (Dianthus), Campions (Silene) and sandworts (Stellaria). The genus originated in the Mediterranean region of Europe, and is now widespread throughout the world.

Though gardeners often use the beautiful Corncockle plant in cottage and meadow gardens, it is considered a weed of wheat fields. (Nb. The Plant is native to the UK, and the word Corn is used to describe wheat in England (hence the common name), Oats in Scotland, and Maize in the USA).

Some varieties of the main species of Agrostemma often grown in gardens, the Corn cockle (Agrostemma githago), with varieties include Common, Milas, Milas Rose Queen, Purple Queen, Contessa Pale Pink, Narrow Corn Cockle, and Ocean pearl Corn Cockle.

Agrostemma githago - Corncockle

Agrostemma githago is an annual plant. It grows to about 2 to 3 feet (60-90 cm) tall. Corncockle features narrow leaves and striking pink to purple flowers.

Agrostemma githago photographs by Ospano and littleherelittlethere.

This plant thrives in full sun and well-drained soil. It's ideal for wildflower gardens, meadows, or for use as a cut flower.

Agrostemma brachyloba - Shortlobe Corncockle

Agrostemma brachyloba is an annual that reaches a height of 1 to 2 feet (30-60 cm). It produces slender leaves and pink flowers with darker spots.

Shortlobe Corncockl prefers a location with full sun and a well-drained soil. It is perfect for mixed borders, meadows, or as a cut flower.

Agrostemma gracilis - Slender Corn Cockle

The annual Agrostemma gracilis grows to 1.5 to 2.5 feet (45-75 cm) tall. Slender Corn Cockle bear linear leaves and carry clusters of pink flowers with dark spots.

It thrives in full sun and a soil with good drainage. It makes a great addition to mixed borders, wildflower meadows, or as a cut flower.

Common Questions

How many members does the Agrostemma genus have?

The Agrostemma genus contains about 12 species.

Do members of Agrostemma make a good garden or landscaping plant?

Yes, Agrostemma, or Corncockle, is popular for its tall, slender stems and vibrant flowers. It's great for wildflower meadows.

Which Agrostemma species are most frequently grown by gardeners?

The most commonly grown species is Agrostemma githago (Corncockle).

Are members of the Agrostemma fragrant?

Agrostemma flowers are not typically known for their fragrance.

What is the perfect location to grow Agrostemma?

Agrostemma prefers full sun and well-drained soil. It does well in poor soils and tolerates dry conditions.

Is Agrostemma invasive in the USA, if so in which states?

Agrostemma githago is considered invasive in some areas in the USA, but is less common now due to changes in agricultural practices.

How do I remove Agrostemma from my garden?

Removal can be done by pulling or digging up the plants. The seeds persist in the soil, so follow-up may be needed.

Summary

The Agrostemma plant genus, also known as Corn Cockle, consists of annual and perennial plants with showy cup-shaped flowers. Native to Europe and Asia, they bloom in vibrant shades of pink, purple, or white. Agrostemma plants thrive in well-drained soil and full sun exposure. They are drought-tolerant and adaptable to various soil types. Regular watering during the blooming season is necessary. Agrostemma is commonly used in cottage gardens and wildflower meadows, adding charm to the landscape while attracting pollinators.

Agrostemma plants enchant with their vibrant cup-shaped flowers in shades of pink, purple, or white, adding a touch of elegance to gardens. Their adaptability to different soil types and drought tolerance make them versatile choices for various garden styles. Whether planted in cottage gardens or wildflower meadows, Agrostemma brings a charming and naturalistic look to the landscape, while also attracting important pollinators like bees and butterflies. With their delightful blooms and ecological significance, Agrostemma is a valuable addition to any garden.

I hope that you enjoyed this guide on Agrostemma. You may also enjoy the following garden growing guides: How to grow Arenaria and Silene plants.