Coronilla

Coronilla: how do you recognise it?

Habit

Rounded, dense shrub about 1 m tall and as wide.

Foliage

Pinnate, with 5–7 rounded, blue-green leaflets covered in a waxy bloom; evergreen.

Flower

Small, bright yellow pea flowers in rounded rings on long stalks, from February to May, often with a second flush.

Scent

Sweet, most noticeable during the day and in sunshine.

Fruit

Slender, jointed pods after flowering.

Flowering: February–May · Plants: April–May · Pruning: June

Why grow it?

• Fragrant yellow flowers from late winter into spring, when little else is in bloom.
• Evergreen, blue-green foliage that adds a fresh note all year round.
• An early source of food for bees and bumblebees on sunny days.
• Tolerates drought and poor, chalky soil: ideal against a sunny wall or in a gravel garden.
• Stays compact and also suits a large pot on a sunny patio.

Coronilla: where does it grow best?

• Full sun, ideally against a south- or west-facing wall that holds warmth and gives shelter.
• Free-draining soil: sand, loam or clay opened up with grit, acid to chalky.
• Dry to moderately moist: it will not tolerate wet feet, especially in winter.
• Sheltered from cold east and north winds.
• Allow about 1 m of space, or grow it in a large pot with a gritty mix.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry

Size

1 m tall, 1 m wide

Hardiness

Half hardy (to -10 °C): protect it in harsh winters

Goes well with

• Rosemary: Evergreen, fragrant and just as fond of sun and drought.
• Lavender: Purple flowers in summer, once the coronilla has finished.
• Spurge: Blue-green leaves and lime-green flowers in spring.
• Rock rose: Mediterranean shrubs that flower in summer, for the same sunny spot.
• Bearded iris: Sword-shaped leaves and flowers in May, in the same dry soil.

Coronilla: when and how to plant it?

Plant in April–May.

1. Plant in April–May, once hard frosts are over: this gives it time to root well before the next winter.
2. Dig a hole twice the size of the root ball and, in heavy soil, mix in coarse sand or grit.
3. Set the plant at the same depth as it was in the pot, 30–40 cm from the wall so that it still gets rain.
4. Allow about 1 m between it and other plants.
5. Water in well straight away, then during dry spells in the first summer.
6. Mulch with gravel and do not pile a thick layer of compost against the stem.

Care

Watering

During dry spells in the first summer; rarely needed after that. In a pot, water regularly but let the compost dry out between waterings.

Feeding

Not needed: like other members of the pea family, it takes nitrogen from the air. In a pot, a little compost in spring is enough.

Mulching

A layer of gravel keeps the base dry and reflects warmth.

Deadheading

You can leave the faded flowers; a light trim after the main flush gives a more compact shrub.

Repotting

In a pot, every two to three years in spring, in a gritty mix.

Tip: Plant it against a south-facing wall by the front door or patio: you will smell the flowers every time you pass, and the wall protects it from hard frost.

Coronilla: when to prune it?

Pruning months: June.

When: After the main flush of flowers, in June, with a light shaping trim.

How:

• Cut the flowered shoots back by up to a third to keep the shrub compact.
• At the same time, remove any dead or frost-damaged twigs.
• Do not cut into old, bare wood: it resprouts poorly from there.

Caution: Do not prune in autumn: the young shoots that grow afterwards are killed by winter frost.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Cuttings

Semi-ripe cuttings of 8–10 cm in July–August, in a mix of sand and cutting compost, under plastic in a bright spot out of strong sun. Overwinter them frost-free.

Seed

Sow in spring, after soaking the seed overnight in lukewarm water. Named forms do not come true from seed.

Coronilla: how does it get through the winter?

Hardy to −10 °C: protect in harsh winters.

• Moderately hardy, to about −10 °C: against a sheltered, sunny wall it survives most Belgian winters.
• In hard frost, cover the shrub temporarily with horticultural fleece and mulch the base.
• In a pot: move it in winter to a cool, bright, frost-free place, such as an unheated greenhouse.
• Take a few cuttings in summer as insurance against a severe winter.

Diseases and pests

• Frost damage: Brown leaves and dead shoot tips after a hard winter. Wait until new leaves appear, then cut out the dead wood.
• Root rot: The shrub suddenly wilts, often after a wet winter in heavy soil. Plant it in a well-drained spot or in a pot.
• Aphids: On young shoots and flower buds. Hose them off with water or leave them to the ladybirds.
• Leggy shrub: After a few years it becomes bare at the base and untidy. A light trim every year helps; replace an old plant with a rooted cutting.

Through the year

• February: The fragrant flowers begin to open.
• March: In flower. Cover with fleece if late frost threatens.
• April: In flower. Plant.
• May: Last flowers of the main flush. Plant.
• June: Trim lightly after flowering. Remove dead twigs.
• July: Take semi-ripe cuttings. Water plants in pots during dry spells.
• August: Take cuttings. Sometimes a second flush.
• November: Move pots to a bright, frost-free place.
• December: Keep fleece at hand for hard frosts.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• Coronilla means ‘little crown’ and refers to the flowers, which are arranged in a ring.
• Like many members of the pea family, it lives with bacteria in nodules on its roots that capture nitrogen from the air.
• The subspecies glauca is named after its blue-green leaves with their waxy bloom.