Hedge mustard

How to recognise it

Habit

Annual or biennial of 30–80 cm, with stiff stems and branches that stand out almost at right angles; the plant looks like a candelabra or skeleton.

Leaf

Lower leaves in a rosette, deeply divided with a large end lobe, rough and hairy. Upper leaves small and spear-shaped.

Flower

Tiny pale yellow flowers of 3–4 mm, packed at the tips of the branches; from May to September.

Fruit/Seed

Short, hairy pods of 1–2 cm that taper towards the tip and are pressed tightly against the stem.

Stem

Tough and hairy, often tinged purple. Stays stiffly upright after the plant has died.

Confusion with

Other Sisymbrium species have long, spreading pods. Charlock has larger, bright yellow flowers and pods with a clear beak.

Flowering: May–September · Pruning: March and July

Why grow it?

• Long flowering season from May to September, with nectar and pollen for small bees, hoverflies and flies.
• Food plant for the caterpillars of white butterflies, such as the green-veined white.
• The stiff brown skeleton with its seed stands all winter: food for birds and shelter for insects.
• A true town plant that copes with dry, stony places where little else grows.
• The young leaves were once eaten as a peppery vegetable, and the plant was known to singers with a hoarse voice.

Hedge mustard: where does it grow best?

• In the wild: verges, waste ground, field margins, wall bases, paths, rubble and farmyards.
• Full sun to light half shade.
• Dry to moderately moist, rich soil, often stony or disturbed; also on sand and rubble.
• In the garden: a rough corner, along a path or wall, or in a butterfly corner with other members of the cabbage family.

Goes well with

• Wild mignonette: Yellow spikes for bees on the same dry, stony ground.
• Viper’s bugloss: Blue flowers for bees and bumblebees in a dry spot.
• Garlic mustard: Another member of the cabbage family, a food plant for whites and the orange-tip, in half shade.
• Bird’s-foot trefoil: Yellow flowers and a food plant for blues on the same sunny verge.

Hedge mustard: when and how to plant it?

1. Hedge mustard usually turns up by itself, with seed brought by birds, shoes or imported soil.
2. If you want it on purpose, buy seed from a nursery or seed supplier for native plants. Never dig plants up from the wild.
3. Sow in March–April or in September on an open, sunny spot and cover the seed lightly.
4. Thin to 25–30 cm between plants.
5. Water until the seedlings are well established; after that it is no longer needed.
6. Choose a spot where it may self-seed, because it will come back every year.

Care

Water

Not needed: it tolerates drought well.

Feeding

Not needed.

Letting it seed

Let some of the plants set seed; cut the rest in July to limit self-seeding.

Weeding

Too many seedlings? Pull them up in spring: they only have a short taproot.

Winter silhouette

Leave the dead stems standing in winter for birds and insects.

Tip: Simply leave a few plants along a wall or path: white butterflies lay their eggs on them, small bees take nectar and in winter birds peck at the stiff skeleton.

Pruning and mowing

Pruning months: March and July.

When: In July, cut some of the stems to limit self-seeding; the rest not until March.

How:

• In July, cut the stems of plants you do not want to self-seed.
• Leave a few plants standing through winter as a stiff skeleton.
• Cut or pull the dead stems in March, before the new rosettes grow.
• Do not put stems with ripe seed on the compost heap if you do not want the plant everywhere.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Self-seeds. To sow it yourself: in March–April or in September; the seed germinates readily.

Hedge mustard: how does it get through the winter?

Hardy to −20 °C.

• Plants that germinate in summer or autumn overwinter as a rosette and flower the following year.
• The stiff brown skeleton stands until spring.
• Very hardy, down to about −20 °C.

Diseases and pests

• Flea beetles: Small holes in the young leaves. Harmless.
• White blister: White, powdery pustules on stems and leaves; the stems may become distorted. Cut off affected parts.
• Self-seeding: Can produce many seedlings in an open garden. Cut some of the stems before the seed ripens.
• Brassica diseases: Like other members of the cabbage family, it can keep clubroot going. Weed it out of the vegetable garden.
• Untidy look: Not everyone likes the skeleton. Give it a spot at the back of a rough corner.

Through the year

• March: Cut the dead stems. Sow.
• April: The rosettes grow. Pull up surplus seedlings.
• May: Flowering begins.
• June: In flower. White butterflies lay eggs on the leaves.
• July: Cut stems if you want fewer seedlings.
• August: Flowers and seed.
• September: Last flowers. Sow.
• November: The stiff skeleton stands; birds search it for seed.
• December: Rest. Rosettes of young plants.

Did you know?

• In French it is also called ‘herbe aux chantres’, the singers’ herb: singers and preachers once used it for their voice.
• ‘Officinale’ shows that the plant was once used in the apothecary’s workshop, the officina.
• The short pods sit so tightly against the stem that they are easy to overlook; yet that is exactly how you recognise the species at once.