Ornamental Annuals

Agrostemma githago 'Ocean Pearls'

corn cockle

Caryophyllaceae

Southeastern Europe, western Asia; naturalized widely

At a Glance

TypeAnnual
HabitUpright
FoliageDeciduous
Height24–36 inches (60–90 cm)
Width6–10 inches (15–25 cm)

Key Features

Attracts Pollinators
Attracts Butterflies
Deer Resistant
Drought Tolerant
Maintenancelow

Overview

A slender, erect annual reaching 24–36 inches (60–90 cm) tall and 6–10 inches (15–25 cm) wide. Stems single or few-branched, covered in fine white hairs, somewhat fragile in exposed locations. Leaves narrow, lance-shaped to linear, 2–4 inches (5–10 cm) long, gray-green, covered with silky white hairs on both surfaces. Ocean Pearls produces white flowers, 1.5–2 inches (4–5 cm) across, with 5 rounded petals veined with fine purple lines at the base, surrounding a white center; the species typically produces magenta-pink flowers. Calyx with 5 long, narrow, leaf-like lobes extending beyond the petals. Blooms from late spring through early summer, with a bloom window of 6–8 weeks. Self-seeds freely where conditions are favorable; seedlings emerge in fall or early spring. Plants establish and decline quickly; the entire life cycle from germination to seed set takes 90–120 days.

Native Range

Agrostemma githago is native to southeastern Europe and western Asia, historically widespread across the Mediterranean region and into Central Asia. Introduced as a weed of cereal grain crops throughout Europe and later naturalized in North America, Australia, and elsewhere. The species grows in disturbed agricultural ground, roadsides, and waste areas at low to moderate elevations.

Suggested Uses

Sown in meadow plantings and cottage-style borders at 6–9 inch (15–23 cm) spacing. Self-seeding habit suits naturalized meadow areas where the colony can persist year to year. Used as a cut flower; stems last 5–7 days in water when cut before petals fully open. All parts of the plant are toxic if ingested; not suited to gardens accessible to children or livestock.

How to Identify

Identified by narrow, linear gray-green leaves 2–4 inches (5–10 cm) long, densely covered in soft white hairs. Flowers 1.5–2 inches (4–5 cm) across with 5 broad petals; Ocean Pearls has white petals with delicate purple veining near the base, contrasting with the magenta-pink of the species. Calyx lobes narrow, extending beyond petals, hairy. Stems hairy, erect, 24–36 inches (60–90 cm). Seedpods ovoid, 0.6–0.8 inch (1.5–2 cm), containing black kidney-shaped seeds.

Appearance

Size & Dimensions

Height2' - 3'
Width/Spread6" - 10"

Colors

Flower Colors

white
purple

Foliage Colors

gray
green

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~6 weeks
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SpringSummer
Blooms late May through July in most temperate climates. In cool coastal climates, bloom extends into August. In zones 7–9, spring-sown seed blooms May through June before summer heat ends flowering. Fall-sown seed (zones 7–10) overwinters and blooms April through May. Total bloom per plant lasts approximately 3–5 weeks.

Detailed Descriptions

Flower Description

White with fine purple veining at petal base

Foliage Description

Gray-green, densely covered with soft white hairs

Growing Conditions

Sun Requirements

Full Sun
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.5(Neutral)
357912
Soil Types
loamsandchalk
Drainage
well drained

Water & Climate

Water Needs

Low

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Direct sow seed in early spring as soon as soil can be worked, or in fall in zones 7–10 for overwintered plants. Seeds germinate in 7–14 days at soil temperatures of 55–65°F (13–18°C). Thin seedlings to 6–9 inches (15–23 cm) apart; crowded plants produce fewer flowers and are more susceptible to lodging in wind. Does not transplant well due to a taproot; sow in final position. Water during establishment; established plants tolerate dry periods of 1–2 weeks but growth and bloom are reduced. Staking may be needed in exposed sites as stems are fragile. Plants are short-lived and decline after seed set; remove and compost after bloom to prevent excessive self-seeding if not desired.

Pruning

Deadhead spent flowers promptly to extend the bloom period by 1–2 weeks and reduce self-seeding; plants self-seed prolifically if seedheads are left to mature. Remove entire plants after bloom ends and seeds are not wanted. If self-seeding is desired, leave a portion of plants to set seed and remove the rest.

Pruning Schedule

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Maintenance Level

low

⚠️ Toxicity Warning

Toxic to pets and humans

Planting Guide

Planting Methods & Timing

Planting Method

direct sow

Direct Sow Timing

Direct sow in early spring as soon as soil is workable, or in fall (zones 7–10) for overwinter bloom.

Days to Maturity

60–75 days

Plant Spacing

8 inches

Companion Planting

Good Companions

Nigella damascena
Centaurea cyanus
Papaver rhoeas
Lychnis coronaria