White horehound

White horehound: how do you recognise it?

Habit

Bushy perennial 40–60 cm tall and 30–40 cm wide, with upright, square stems that become a little woody at the base.

Leaves

Round to oval, 2–5 cm, opposite and strongly wrinkled; covered in white, felted hairs that make them grey-green.

Flower

Small white lipped flowers in dense whorls around the stem, from June to August.

Scent

The leaves smell aromatic when brushed and taste very bitter.

Fruit

Calyces with small hooks that cling to clothes and fur and so spread the seed.

Flowering: June–August · Harvest and fruit: June–August · Sowing: April–May · Plants: April–May · Pruning: March

Why grow it?

• Grey, woolly foliage that looks good all season, even when the plant is not in flower.
• Flowers from June to August and is a rich nectar source for bees and bumblebees.
• Drought tolerant: ideal for gravel gardens, dry borders and poor, chalky soil.
• A traditional herb for bitter tea and sweets, a fun addition to the herb garden.
• Low maintenance: no feeding and no watering after the first summer.

White horehound: where does it grow best?

• Full sun; in shade the plant becomes floppy and loses its grey colour.
• Dry to normal, well-drained soil: sand, loam or chalky clay, neutral to chalky. Poor soil suits it well.
• Dislikes wet feet, especially in winter. Improve heavy clay with coarse sand or gravel.
• Wind and heat are no problem, so a sheltered spot is not needed.
• Allow about 40 cm between plants.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Neutral or chalky

Moisture

Dry

Size

0.5 m tall, 0.4 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Lavender: Same dry, sunny spot; purple flowers beside grey foliage.
• Common sage: Suits the same herb border and needs the same care.
• Thyme: A low, scented ground cover for the edge.
• Catmint: Blue flowers that go with the grey leaves all summer.
• Blue fescue: A blue-grey grass that strengthens the silvery tones.

White horehound: when and how to plant it?

Plant in April–May.

1. Plant or sow in April–May, when the soil has warmed up and the last frosts are over.
2. Dig a hole as deep as the root ball and a little wider. Do not add compost or fertiliser; in heavy soil mix in some gravel or sand.
3. Set the plant at the same depth as in its pot and firm the soil gently.
4. Space plants about 40 cm apart. When sowing, scatter the seed on the surface and barely cover it.
5. Water thoroughly once when planting; after that only during long dry spells in the first year.
6. A thin layer of gravel or grit around the base keeps the foliage dry. Avoid a thick layer of compost.

Care

Water

In the first summer during long dry spells; after that watering is rarely needed.

Feeding

Do not feed: on poor soil the foliage stays compact, grey and aromatic.

Mulching

Gravel or grit only. A thick layer of compost keeps the base too damp.

Spent flowers

Cut them off if you do not want the plant to self-seed; leave them if you want seedlings or seed.

Harvesting

Pick young tips and leaves before and during flowering and dry them in an airy, shaded place.

Tip: Give it a poor, dry spot in full sun and do not feed it: the foliage stays grey and compact and the plant lasts for years.

White horehound: when to prune it?

Pruning months: March.

When: From late February to March, when the new shoots start to grow.

How:

• Cut the old stems back to 5–10 cm above the ground.
• Remove dead or damaged pieces right at the base.
• In summer, cut off spent tips to limit self-seeding.
• Replace old, bare plants after a few years with young ones.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Sow outdoors in April–May, on the surface, and thin to about 40 cm. Seed germinates slowly and unevenly; self-sown seedlings can be moved while they are young.

Cuttings

In May–July take tip cuttings of 8–10 cm in sandy cutting compost, with the lower leaves removed. Keep them slightly moist until they root.

White horehound: how does it get through the winter?

Hardy to −25 °C.

• Hardy to about −25 °C: in Belgium no protection is needed.
• Wet soil is more dangerous than frost: make sure the drainage is good and do not let a thick layer of wet leaves lie on the plant.
• In a pot: use sandy compost and a pot with a drainage hole; in winter place it against a wall under a canopy.

Diseases and pests

• Root rot: The plant dwindles and dies in wet soil, especially in winter. Plant in free-draining soil with gravel or sand, if needed on a slight mound.
• Floppy, green growth: Too much shade or feeding. Move the plant to a sunny spot and stop feeding.
• Self-seeding: Many seedlings around the plant. Cut off the flowers before the seed ripens or weed out the young plants.
• Mould on the leaves: The woolly foliage can go mouldy in a wet, shady summer. Give it space and sun and cut off affected parts.

Through the year

• March: Cut back to 5–10 cm. Renew old plants.
• April: Plant and sow. Do not feed.
• May: Plant and sow. Take cuttings. Thin seedlings to 40 cm.
• June: Flowering begins. Harvest young tips.
• July: Full flower, lots of bees. Harvest and dry.
• August: Last flowers. Cut off spent tips or leave them for seed.
• October: Clear debris and wet leaves from the plant.
• December: Rest. Make sure the soil drains well.

Edible and useful

Leaves (June–August)

Pick the young tips and leaves from June to August, before and during flowering, on a dry day. The grey, woolly leaves smell aromatic and taste very bitter, with a hint of mint. They have long been used for bitter herbal tea and for horehound drops, old-fashioned British and American sweets; in everyday cooking they are not used.

Storing

Dry the tips in small bunches, upside down somewhere airy and shady, or loose on a rack. Strip off the leaves once they are crisp and keep them in the dark in a closed jar for up to a year.

Caution: Horehound is a bitter herb: use it in small amounts and not every day for long periods. Not during pregnancy or breastfeeding, nor for young children. Horehound tea and sweets are not medicines: if symptoms persist, see a doctor. The hooked calyces cling to clothes and pets’ fur, so cut the tips before they have finished flowering.

Eating and using is at your own risk: see the terms of use.

Recipes

• Horehound drops (Other · ± 500 g of sweets · 1 hr)
• Horehound tea with honey (Tea · 1 cup · 10 min)

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The grey, felted covering of hairs protects the leaves from strong sun and too much evaporation.
• Horehound candy is a traditional sweet in Britain and the United States.
• In Australia, New Zealand and parts of the United States the plant has naturalised and is regarded as a weed.