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Silene flos-cuculi

ragged-robin

Caryophyllaceae Europe and western Asia

Attracts Pollinators Attracts Butterflies

SunFull Sun – Part Shade

WaterHigh

HardinessZones 4–8

Overview

Silene flos-cuculi, formerly Lychnis flos-cuculi, is a clump-forming perennial 12-32 inches (30-80 cm) tall with slender, branching, slightly sticky stems rising from a basal rosette. The lower leaves are spoon-shaped while the stem leaves are narrow and lance-shaped, paired and untoothed. From late spring into summer it carries loose, open clusters of rose-pink flowers, each 1.2-1.6 inch (3-4 cm) across with five petals that are each split into four narrow, spreading lobes, giving the bloom a ragged, frayed outline. A white-flowered form occurs occasionally. The flowers are followed by small capsules that release many tiny seeds. S. flos-cuculi grows in damp meadows, fens, marshes, and wet woodland edges across Europe and western Asia, and has naturalized locally in North America. It is short-lived but self-sows where the ground stays moist. The thin stems can flop in rich soil or shade and may lean on neighbouring plants for support.

Native Range

Silene flos-cuculi is native across Europe and into western Asia, from Ireland and Scandinavia to the Mediterranean and the Caucasus. It grows in damp grassland, fens, and marshes, and has naturalized in scattered parts of North America.

Suggested Uses

Planted in bog gardens, rain gardens, pond and stream margins, and damp wildflower meadows. It is used in pollinator and cottage-style borders where soil stays moist. The ragged pink flowers suit naturalistic and conservation plantings on wet ground.

How to Identify

Ragged-robin is known by its rose-pink flowers whose five petals are each cut into four slender lobes, giving a ragged star 1.2-1.6 inch (3-4 cm) wide. The branching, slightly sticky stems carry narrow paired leaves and stand 12-32 inches (30-80 cm) tall in damp ground. The deeply divided petals separate it from campions and pinks in the same family, which have notched or rounded petals.

Appearance

Size & Dimensions

Height1' - 2'8"

Width/Spread1' - 1'6"

Reaches mature size in approximately 2 years

Colors

Flower Colors

pink

white

Foliage Colors

green

Bloom Information

Bloom Period

~8 weeks

Spring Summer

Flowering runs from May to July, with a peak in late spring and early summer. Each branched stem opens a succession of ragged pink flowers over several weeks. Seed capsules ripen through summer, and cutting back after the first flush can prompt a lighter second show.

Detailed Descriptions

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-10 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 Range5.5 - 7.0(Neutral)

357912

Soil Types

clay loam silt

Drainagemoist

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Time to Maturity

1-2 years

Care & Maintenance

Care Guide

Grow Silene flos-cuculi in full sun to light shade in consistently moist to wet soil, including clay and loam, at a slightly acidic to neutral pH. It is hardy through USDA zones 4 to 8 and tolerates seasonal waterlogging that many border perennials cannot. In dry or fertile soil the stems weaken and flop, so a moist, open position keeps them upright. Plants are short-lived, often persisting three to four years, but renew themselves from self-sown seedlings. Divide clumps in spring or autumn to maintain vigour. No staking is needed where plants grow among supporting vegetation.

Pruning

Cut stems back after the first flush of bloom to tidy the plant and prompt further flowers. Leave some seed heads at the end of the season to allow self-seeding. Clear dead growth in late autumn or early spring.