Wild mignonette

How to recognise it

Habit

Biennial or short-lived perennial, 30–75 cm, branched and somewhat bushy, with ascending stems.

Leaf

Once or twice pinnately cut into narrow lobes with a wavy edge; in a rosette in the first year.

Flower

Small pale yellow flowers with six petals, the upper ones deeply cut, in dense, conical spikes; June to September. Faintly scented.

Fruit/Seed

Upright, oblong capsules with three teeth that stand open at the top even before ripening; with glossy black seeds.

Roots

Deep, strong taproot: very drought-tolerant, but the plant does not like being moved.

Confusion with

Weld is taller, up to 1.5 m, with long, narrow, undivided leaves and one long, narrow spike of four-petalled flowers. Garden mignonette has strongly scented flowers and is sown as an annual.

Flowering: June–September · Pruning: March and September

Why grow it?

• The yellow-face bee Hylaeus signatus collects pollen only from mignonettes; other wild bees, bumblebees and hoverflies visit the flowers too.
• Long flowering from June into September, in the driest spots of the garden.
• Food plant of the Bath white, a rare migrant butterfly; small whites also lay eggs on it now and then.
• A true pioneer: it germinates on bare, stony ground and helps to green it again.
• With its deep taproot it gets through dry summers without watering.
• A relative of weld, an old dye plant once used to dye textiles yellow.

Wild mignonette: where does it grow best?

• In the wild: railway embankments, quarries, waste ground, port and industrial sites, dykes, dunes and sunny road verges.
• Full sun on dry, free-draining soil: sand, gravel, rubble or chalky loam. Poor soil is fine.
• Likes open, disturbed ground; in a dense, fertile sward it disappears.
• In the garden: gravel garden, rock garden, dry border, a stony strip along the patio or a dry, poor bank.

Goes well with

• Viper’s-bugloss: Blue flowers on the same dry, stony ground; a favourite of bees and bumblebees.
• Great mullein: Tall yellow candles that catch the eye in a gravel garden.
• Wild marjoram: Purple heads for butterflies, on dry, chalky soil.
• Bird’s-foot trefoil: Low yellow flowers and food plant of the common blue.
• Wild carrot: White umbels with a dark central floret, for beetles and hoverflies.

Wild mignonette: when and how to plant it?

1. Buy seed or pot-grown plants of native origin from a nursery specialising in wild plants.
2. Ideally sow outdoors in autumn (September–November), thinly on bare, loosened soil; press in and barely cover. After a cold winter the seed germinates more readily.
3. Sowing in March–April is possible too, but germination is often slower and more erratic.
4. Plant young plants in autumn or spring, 30–40 cm apart; put them in their final place straight away, as the taproot dislikes being moved.
5. Water only in dry spells during the first few weeks; after that, not at all.
6. Never dig up plants from the wild: with its taproot it rarely survives, and seed is easy to obtain.

Care

Water

Not needed, except just after planting. Wet, heavy soil is its worst enemy.

Feeding

Never: on poor soil it stays compact and sturdy; on rich soil it flops and disappears among other plants.

Self-seeding

It lives only a few years: let it drop seed every year so young plants replace the old ones.

Open ground

Keep some bare soil or gravel around the plants: seedlings need light and open ground.

Weeding

In spring, remove grasses and fast spreaders around the young plants.

Tip: Sow wild mignonette in a strip of rubble or gravel along a wall or patio: it grows and flowers better there than in the best garden soil.

Pruning and mowing

Pruning months: March and September.

When: In March, before new growth starts; in September, part of the seed spikes if you wish.

How:

• Leave faded stems standing through autumn and winter: the seed drops and the stems shelter insects.
• In March, cut the old, dry stems back to just above the rosette or the ground.
• For fewer seedlings, cut off part of the seed spikes in September.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Collect ripe, black seed from the open capsules in August–September. Sow outdoors on bare soil in autumn.

Self-sown seedlings

In an open, sunny spot it seeds itself. Move seedlings while young, when they have only a few leaves.

Wild mignonette: how does it get through the winter?

Hardy to −25 °C.

• In its first year it overwinters as a leaf rosette; older plants die back above ground and regrow from the root in spring.
• The dry stems with empty capsules stay standing and shelter insects.
• Hardy to about −25 °C, but in wet winters on heavy soil the root rots.

Diseases and pests

• Root rot: On wet, heavy soil the taproot rots in winter. Plant in sand, gravel or rubble, or high on a bank.
• Disappearing: As a short-lived pioneer it vanishes when the ground grows over. Keep patches open and let it seed.
• Caterpillars: Caterpillars of white butterflies sometimes eat the leaves. The plant recovers; leave them, they belong in a wildlife garden.
• Slugs: They like young seedlings in a wet spring. Sow in a dry, stony spot or protect the seedlings for a while.

Through the year

• March: Cut old stems back. The rosettes start growing.
• April: Plant out young plants. Weed around the rosettes.
• May: Flower stems grow. Watch for slugs on seedlings.
• June: Flowering begins. Bees and hoverflies on the spikes.
• July: Full flower. Look for small black yellow-face bees on the flowers.
• August: Flowering and first ripe seed. Collect seed.
• September: Last flowers. Cut off part of the seed spikes if you wish.
• October: Sow outdoors. Planting is still possible.
• November: Leave the stems as winter shelter.
• December: Dormant. Rosettes of young plants stay green.

Did you know?

• Reseda is thought to come from the Latin ‘resedare’, to calm or soothe; the Roman writer Pliny already mentions the plant by that name.
• The English name mignonette comes from the French for ‘little darling’, a name given to the scented garden mignonette.
• Its relative weld was an important dye plant for centuries: until the 19th century it was used to dye wool, linen and silk yellow.