Sweet box

Sweet box: how do you recognise it?

Habit

Compact, evergreen shrub 0.8–1 m tall and wide, spreading slowly by suckers.

Foliage

Narrow, lance-shaped and pointed, 5–10 cm long; glossy, dark green and leathery.

Flower

Small, white with pink-tinged stamens, in small clusters at the leaf joints, from December to March.

Scent

Sweet and strong, reminiscent of honey and vanilla; it carries several metres, especially on mild days.

Fruit

Small, round, black berries after flowering. Do not eat.

Roots

Fibrous, shallow and suckering; they dislike drying out.

Flowering: December–March · Plants: April–May and September–October · Pruning: April

Why grow it?

• Flowers in the dark months from December to March with a strong, sweet scent.
• Evergreen, glossy foliage that gives structure all year.
• Grows in shade and partial shade, even under trees where little else flowers.
• On mild winter days bees visit the tiny flowers, one of the few sources of nectar at that time.
• Little pruning and little upkeep needed; thrives without fuss.

Sweet box: where does it grow best?

• Partial shade to shade; it also tolerates dry shade under trees and a cold north-facing aspect.
• Humus-rich, well-drained soil: sand, loam or clay, acid to chalky.
• Normally moist; it grows best in soil that does not dry out, but does not tolerate permanently wet feet.
• Sheltered from cold, drying east winds, which can damage the foliage.
• Allow 1 m per plant; for a dense clump, plant 60–80 cm apart.

Light

Partial shade and shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Normal

Size

1 m tall, 1 m wide

Hardiness

Hardy (to -20 °C)

Goes well with

• Hellebore: Also flowers in winter, in the same shade.
• Snowdrop: Flowers early in spring among the evergreen leaves.
• Barrenwort: A shade ground cover that flowers in spring.
• Ferns: Soft, fine fronds beside the stiff, glossy foliage.
• Bergenia: Large, round leaves and pink flowers in spring.

Sweet box: when and how to plant it?

Plant in April–May and September–October.

1. Plant in April–May or September–October, when the soil is neither frozen nor waterlogged.
2. Dig a hole twice as wide as the root ball and mix in a few spades of leaf mould.
3. Set the plant at the same depth as in its pot and firm the soil well.
4. Leave 1 m between plants, or 60–80 cm for a dense clump.
5. Water in generously straight away and keep the soil moist in the first year.
6. Spread a layer of leaf mould or bark mulch around the base.

Care

Water

In the first year, water generously once a week in dry weather. After that it usually copes in shade; water extra in dry summers.

Feeding

Little needed. A layer of compost or leaf mould in spring is enough.

Mulching

A layer of leaf mould in spring or autumn keeps the soil cool, moist and rich in humus.

Tidying

In spring, remove dead or damaged wood; leave the flowers alone in winter.

Pot

Use a large, well-drained pot and a humus-rich compost; stand it by a door to enjoy the scent.

Tip: Plant it by a door, path or seat in the shade: the winter scent can be smelt several metres away. Give it humus-rich soil and shelter it from cold east wind.

Sweet box: when to prune it?

Pruning months: April.

When: In April, straight after flowering. Little pruning is needed.

How:

• Remove dead, damaged and crossing branches completely.
• Shorten long or stray branches to a side shoot to keep the shape.
• An old, bare shrub can be cut back by half after flowering; it will regrow.
• Remove suckers where the shrub must not spread.

Caution: Do not prune in autumn or winter: you would cut off the buds and lose the flowers.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Cuttings

In July–September, take 8–10 cm cuttings of semi-ripe shoots, strip the lower leaves, and insert them in a sandy mix under plastic or in a cold frame. Rooting takes a few months, sometimes until after winter.

Division

In April–May, after flowering, detach a piece with roots and shoots from the edge of the shrub and replant it straight away elsewhere.

Sweet box: how does it get through the winter?

Hardy to −20 °C.

• Hardy to about −20 °C: no protection is needed in Belgian winters.
• In hard frost or dry wind the flowers and foliage may suffer for a while, but it recovers easily.
• In a pot: stand the pot against a wall or by a sheltered door and wrap it in hessian so the roots do not freeze.

Diseases and pests

• Brown leaves: Usually caused by hard frost or cold, dry wind in winter, or by drought. Cut damaged stems back in spring.
• Yellow leaves: Often caused by wet feet or soil that is too compacted and poor. Improve drainage and add leaf mould.
• Scale insects: Small brown shields on branches and leaves, sometimes with sticky honeydew. Rub them off or prune affected branches.
• Box blight: As a relative of box, it may be hit by the same fungi: brown spots and leaf drop. Clear fallen leaves and keep it airy.

Through the year

• January: Flowering: scent in the garden. No pruning.
• February: Flowering. Enjoy the scent by the door.
• March: End of flowering.
• April: Prune after flowering. Plant. Apply compost.
• May: Plant. Water young plants.
• June: Water in dry weather.
• July: Take cuttings. Water in dry weather.
• August: Take cuttings.
• September: Plant. Take cuttings.
• October: Plant. Mulch with leaf mould.
• December: Flowering begins: scented little flowers.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• Sweet box belongs to the box family (Buxaceae), like common box.
• The flowers are small, but the scent is so strong that you can smell it several metres away on a mild winter day.
• It flowers in midwinter, when few other plants are in bloom; on mild days the little flowers feed bees.