PL. —Agrostemma githagoBotanical illustration — drop image
Agrostemma githago

Agrostemma

SpringSummer
2a11bHardiness zone
Peak bloom windowZone 6b · frost-offset weeks
Winter
Not in bloom
Spring
Peak bloom
Summer
In bloom
Fall
Not in bloom
Peak bloom
In bloom
Background

Agrostemma githago — corn cockle — is a Eurasian native that followed grain cultivation across Europe for centuries, once a common weed of wheat fields before modern seed-cleaning all but eliminated it from working farms. It has since become a cutting-garden favorite instead: tall, wiry stems carry single magenta-pink flowers with narrow petals and faint dark veining, held above silvery, grass-like foliage. Popular strains include 'Milas' (deep magenta) and 'Ocean Pearls' (a paler pink-to-white mix).

It is a true hardy annual — direct sow into cool soil in very early spring, or in fall in mild climates, for the largest plants and earliest bloom; it resents root disturbance and does not transplant well. The seeds, and to a lesser extent the leaves, are toxic if ingested — historically responsible for livestock and human poisoning when they contaminated grain — so keep it away from grazing animals and out of reach of pets. Once established it self-seeds readily.

Care guide
SunFull sun
WaterLow to moderate; drought tolerant once established
SoilAverage to poor, well-draining
Spacing6–9 inches
Height24–36 inches
Zone2a – 11b
WinterHardy annual — self-seeds freely once established.
Direct sowFrost hardy
Seasonal tasks
spring
sowDirect sow into cool soil in very early spring, or in fall in mild climates for larger plants — dislikes root disturbance, so avoid transplanting
watchThin seedlings to final spacing; stake or grow through hoops in exposed sites since stems are thin and wiry
summer
cutCut for fresh arrangements as flowers open
watchKeep away from livestock and pets — seeds and foliage are toxic if ingested
fall
watchAllow some seed heads to ripen and drop for self-seeding
Common problems

Damping Off

Symptoms

Seedlings collapse at the soil line with thin, water-soaked stems; seeds may fail to emerge or rot before sprouting.

Treatment

Sow in well-draining mix, avoid overwatering, and ensure good airflow. Remove affected seedlings and let the surface dry between waterings.

Root rot

Symptoms

Plants wilt, yellow, and stunt even in moist soil; lower stems and roots turn brown, soft, and mushy and the plant may collapse. Most common in heavy, wet, or poorly drained ground.

Treatment

Improve drainage and stop overwatering, and never plant too deep. Lift and destroy badly affected plants along with the soil around the roots. Grow in raised or free-draining beds to prevent it returning.

Rust

Symptoms

Orange to brown raised pustules on the undersides of leaves, with yellow spotting on the upper surface. Heavy infections cause leaves to yellow and drop.

Treatment

Remove and destroy infected leaves. Avoid overhead watering and improve air circulation. Apply a sulfur or copper-based fungicide if it spreads. Clear plant debris in fall.

Powdery mildew

Symptoms

White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.

Treatment

Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.