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Centranthus spp.

valerian

Caprifoliaceae Mediterranean and southern Europe

Attracts Pollinators Attracts Butterflies Deer Resistant Drought Tolerant Fragrant (moderate)Container Friendly

SunFull Sun – Part Shade

WaterLow · drought-tolerant

HardinessZones 5–8

Overview

Centranthus spp. is a genus of about ten annual and perennial herbs in the family Caprifoliaceae, native to the Mediterranean region and adjacent parts of Europe and western Asia. The most familiar species, C. ruber, is a bushy, short-lived perennial 1-3 feet (30-90 cm) tall and wide, with fleshy, blue-green, lance-shaped leaves on branching, slightly woody-based stems. From late spring into autumn it carries dense rounded clusters of small, faintly fragrant, spurred flowers about 0.2 inch (5 mm) long, in deep reddish-pink, crimson, or white. The long bloom season and abundant seed allow the genus to colonize walls, rocky slopes, cliffs, and dry banks, often rooting in lime mortar and crevices with little soil. Plants tolerate drought, poor fertility, and alkaline conditions but are short-lived and tend to grow leggy and flop on rich or shaded sites. C. ruber has naturalized across western North America, the British Isles, and Australia, and is treated as an environmental weed in parts of California and the Pacific Northwest. Removing spent flower heads extends the display and curbs self-sowing.

Native Range

Native to the Mediterranean basin and neighboring parts of southern and western Europe and western Asia, on rocky slopes, cliffs, and old walls.

Suggested Uses

Grown in dry gardens, gravel beds, rock gardens, and the tops and faces of retaining walls, where it roots in minimal soil. It suits Mediterranean and coastal plantings and combines with lavender, santolina, and ornamental grasses. Self-sown seedlings naturalize readily and may need thinning.

How to Identify

Recognized by smooth, blue-green, slightly fleshy leaves in opposite pairs and branching stems topped with dense domed clusters of small spurred flowers. Each tubular flower is about 0.2 inch (5 mm) long with a slender nectar spur at the base and a single stamen. Flower color ranges from brick-red and pink to pure white, sometimes on plants growing side by side. Seeds bear a feathery pappus and disperse on the wind.

Appearance

Size & Dimensions

Height1' - 3'

Width/Spread1' - 3'

Colors

Flower Colors

red

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~14 weeks

Spring Summer Fall

Flowers from May to September, a span of roughly 12-16 weeks when spent heads are removed. A lighter second flush often follows shearing in midsummer. The faintly sweet flowers draw bees, butterflies, and day-flying hawk-moths.

Detailed Descriptions

Flower Description

reddish-pink, crimson, or white

Foliage Description

blue-green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

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 Range6.5 - 8.0(Alkaline)

357912

Soil Types

loam sand chalk rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

Flowers in the first or second year from seed.

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grows in full sun on lean, sharp-draining soil with a pH near 6.5-8.0, including chalky, rocky, and gravelly ground. Established plants are highly drought tolerant and need no supplemental water in most climates. Rich, moist, or shaded conditions produce floppy growth and shorten the plant brief life. Shearing after the first flush of bloom encourages rebloom and reduces self-seeding. Plants are short-lived but renew themselves freely from seed. No feeding is needed on average soils.

Pruning

Spent flower clusters are sheared off through the season to prolong bloom and limit seedlings. Stems are cut back hard in late autumn or early spring to remove the previous year growth. Plants resprout from the woody base.

Pruning Schedule

summerearly spring