Common centaury

How to recognise it

Habit

Biennial, sometimes annual, 10–50 cm tall, with a leaf rosette at the base and an upright, square stem that branches at the top.

Leaf

Rosette leaves obovate, 2–5 cm, with 3–7 distinct, almost parallel veins; the rosette is still present at flowering. Stem leaves smaller, narrower and opposite.

Flower

In June–September dense, fairly flat clusters of pink flowers of about 1 cm, with five pointed lobes on a narrow tube. They only open in sunshine and close in dull weather and in the evening. The yellow anthers twist like a corkscrew after shedding their pollen.

Fruit

A narrow, elongated capsule with very fine, dust-like seed.

Roots

A thin, little-branched taproot.

Confused with

Lesser centaury is smaller and more loosely branched, with no leaf rosette at flowering. Seaside centaury grows on the coast and has narrow, almost linear leaves.

Flowering: June–September · Pruning: September–October

Why grow it?

• A graceful plant with bright pink flowers from June to September, when many spring flowers of poor grassland are already over.
• Small bees, hoverflies and butterflies visit the flowers.
• A pioneer of open, poor ground and a sign of varied, unfertilised soil.
• A historic plant: because of its bitterness it was used for centuries in folk medicine and in herbal bitters.
• It suits a poor wildflower meadow, a heather garden or a sunny, sandy spot where little else grows.

Common centaury: where does it grow best?

• In the wild: woodland clearings, forest paths, woodland edges, heath and dune margins, poor grassland, dykes, quarries and verges.
• Sun to light partial shade, in an open spot with little competition from grasses.
• Poor, free-draining soil: sand, loam or chalk, dry to moderately moist.
• In the garden: a poor wildflower meadow, a heather garden, a sunny, sandy bank or the open edge of a gravel path.

Goes well with

• Perforate St John’s-wort: Yellow flowers in summer, also a plant of open woodland edges and clearings.
• Harebell: Blue bells beside the pink stars on poor soil.
• Heather: On the same poor, sandy soil, with pink flowers in August–September.
• Bird’s-foot trefoil: Yellow flowers in the same poor grassland.
• Sheep’s-bit: Blue pompons on acid sand, loved by wild bees.

Common centaury: when and how to plant it?

1. Buy seed or young plants from a nursery specialising in native plants. Never dig up plants from the wild.
2. Sow in September–October or in March–April. The seed is as fine as dust: mix it with fine sand, scatter it on the surface and do not cover it, as it needs light to germinate.
3. Sow on an open, bare patch or in a pot of sandy, poor compost, and keep it moist until germination.
4. Plant out young plants with their root ball in autumn or spring, in small groups, 15–20 cm apart.
5. No fertiliser and no compost: on rich soil it disappears under taller plants.

Care

Water

Only when sowing and until young plants are established. After that it copes well with drought.

Feeding

Never: centaury likes poor soil.

Open ground

It needs bare patches to germinate. Scratch up a little soil now and then or leave some bare spots in the meadow.

Mowing

Do not mow until September–October, after the seed has set, and remove the cuttings.

Let it seed

Leave the spent stems until the capsules are ripe: that way the plant stays on your plot.

Tip: Centaury wants open ground. Make a few bare patches in your poor meadow, for example by scratching up some soil in autumn, and scatter the dust-like seed there.

Pruning and mowing

Pruning months: September–October.

When: No pruning. Mow the meadow or plot in September–October, after the seed has set.

How:

• Leave the stems until the capsules are brown and dry.
• Shake them over a bare patch to get new plants.
• Then mow and remove the cuttings, to keep the soil poor.

Caution: Do not mow over the plants in June–August: you would lose flowers and seed.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

The only method: sow the dust-like seed on the surface in autumn or spring, without covering it. Plants from an autumn sowing usually flower the following year.

Self-seeding

On open, poor ground it self-seeds; the young rosettes often appear in autumn.

Common centaury: how does it get through the winter?

Hardy to −25 °C.

• Young plants spend the winter as a small, flat leaf rosette.
• Hardy: wet soil and dense vegetation are a bigger problem than frost.
• The dry little stems with empty capsules stay standing for a long time.

Diseases and pests

• Crowded out: On rich soil or in tall grass it disappears after a few years. Make the soil poorer, mow late and keep some bare patches.
• Gone after flowering: That is normal: it is a biennial. Let it seed or sow a little more.
• Slugs: Young rosettes are vulnerable to slugs, especially in a damp autumn. Sow in a sunny, dry spot.
• Flowers stay closed: In dull weather and in the evening the flowers stay closed; that is normal.
• Sowing fails: Seed sown too deep does not germinate. Scatter it on the surface and just press it down.

Through the year

• March: Sow on the surface, do not cover.
• April: The rosettes grow. Do not mow around the plants.
• June: Flowering begins.
• July: Full flower; the flowers open in sunshine.
• August: Flowers and the first capsules.
• September: Seed ripens. After seed set, mow and remove the cuttings.
• October: Sow for next year. New rosettes appear.
• December: Rosettes dormant.

Did you know?

• The name Centaurium refers to the centaur Chiron from Greek mythology, who according to legend treated a wound with this herb.
• Later, people read Centaurium as ‘centum aurum’, a hundred gold pieces. In German this became Tausendgüldenkraut, the herb of a thousand guilders, and in Dutch duizendguldenkruid.
• Because of its bitter compounds, it was once used in herbal bitters and liqueurs.