Sweet osmanthus

Sweet osmanthus: how do you recognise it?

Habit

Dense, upright shrub or small tree; in our climate usually 2–3 m tall and about 2 m wide. Slow-growing.

Leaves

Elliptic to oblong, 7–15 cm, leathery, glossy dark green, smooth-edged or finely toothed, in opposite pairs.

Flowers

Tiny, creamy-white flowers about half a centimetre across in clusters in the leaf axils, in September–October. There is also an orange-flowered form.

Scent

Sweet and fruity, like apricot or peach; it carries surprisingly far, especially on mild, still days.

Roots

Fairly compact: it copes well with life in a large pot.

Flowering: September–October · Plants: April–May · Pruning: April

Why grow it?

• One of the most deliciously scented shrubs: apricot fragrance in autumn, when few other plants are still scented.
• Evergreen: a full, glossy shrub all year round.
• Does well in a large pot on the patio, where you can enjoy the scent up close.
• Grows slowly and stays neat, with little pruning.
• Brings a touch of the Asian garden to a sheltered town garden or courtyard.

Sweet osmanthus: where does it grow best?

• Sun to partial shade, ideally against a south- or west-facing wall, sheltered from cold east and north winds.
• Humus-rich, well-drained sandy or loamy soil, acid to neutral. On chalky soil the leaves turn yellow.
• Moderately moist: do not let it dry out, but avoid waterlogging, especially in winter.
• In a pot: a large container with drainage holes, filled with good potting compost mixed with some sand or fine grit.
• Allow about 2 m; plant at least 50 cm from the wall.

Light

Sun and partial shade

Soil type

Sand or loam

Acidity

Acid or neutral

Moisture

Normal

Size

3 m tall, 2 m wide

Hardiness

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

Goes well with

• Camellia: Another evergreen East Asian shrub for acid to neutral soil, flowering at a different time of year.
• Japanese anemone: Flowers at the same time, in September–October, with pink or white blooms in front of the dark shrub.
• Hydrangea: Enjoys the same sheltered spot and acid to neutral soil.
• Ferns: Fine green fronds at the base, in the shade of the shrub.

Sweet osmanthus: when and how to plant it?

Plant in April–May.

1. Plant in April–May, after the worst frosts, so it can root in well before winter.
2. Dig a hole twice as wide as the root ball and mix compost or leaf mould into the soil. On heavy soil, put some gravel in the bottom.
3. Set the root ball at the same depth as in the pot and firm the soil well.
4. In a pot: choose a container at least 40–50 cm across with a drainage layer of gravel or crocks.
5. Water in thoroughly straight away, then regularly during the first summer.
6. Spread a mulch of leaf mould or bark around the base.

Care

Water

In open ground only in dry spells. In a pot, regularly in summer; sparingly in winter, but never let the root ball dry out completely.

Feeding

In May, compost or an organic shrub fertiliser. Potted plants get a little liquid feed every two weeks from May to July. No feeding after August.

Mulching

A layer of leaf mould or bark in spring keeps the roots cool and protects them in winter.

Repotting

Every 2–3 years in spring, into a slightly larger pot with fresh compost.

Overwintering

In severe frost, move potted plants into a cool, bright, frost-free place, such as an unheated greenhouse or a garage with a window.

Tip: Put it by the patio, the front door or a window: you hardly see the flowers, but the scent carries far, especially on a mild autumn evening. If you are unsure whether it is hardy enough in your garden, grow it in a large pot.

Sweet osmanthus: when to prune it?

Pruning months: April.

When: It needs little pruning. Prune in April, once the worst frosts are over.

How:

• Cut frosted or brown stems back to healthy wood.
• Lightly shorten stray shoots to keep the shrub dense and shapely.
• Never prune hard: it grows slowly and recovers slowly.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Semi-ripe cuttings

In July–August: cuttings of 10–15 cm, lower leaves removed, in a moist mix of compost and sand under plastic, ideally with bottom heat. They are slow to root.

Layering

In spring, peg a low stem into the soil after lightly nicking it; sever it after one to two years.

Sweet osmanthus: how does it get through the winter?

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

• Moderately hardy, to about −10 °C. In a severe Belgian winter it can be killed in open ground.
• Plant it against a sheltered wall and spread a thick mulch over the roots in autumn. Wrap it in horticultural fleece in severe frost.
• In a pot: bring it into a cool, bright, frost-free place in severe frost and put it back outside in mild weather.
• Water little in winter, but never let the root ball dry out completely.

Diseases and pests

• Frost damage: Brown, withered leaves and dead twigs after a hard winter. Cut back to healthy wood in April; it usually regrows.
• Scale insects: Brown or white bumps on the stems and leaf undersides, with sticky leaves. Mainly on potted plants overwintered indoors. Scrub off with a soft brush and soapy water.
• Yellow leaves: Yellow leaves with green veins point to soil or water that is too limy. Water with rainwater and give a feed for acid-loving plants.
• Root rot: Limp, wilting leaves while the compost is wet. Ensure good drainage, do not leave water in the saucer and water less in winter.

Through the year

• January: Potted plant cool and frost-free, little water. In open ground, protect in severe frost.
• April: Plant. Cut out frost damage and prune lightly. Move pots back outside.
• May: Plant. Give compost or shrub fertiliser.
• June: Water in dry spells, especially in pots. Feed potted plants.
• July: Take semi-ripe cuttings. Water in dry spells.
• August: Take cuttings. Stop feeding.
• September: Flowering begins: fragrant little flowers in the leaf axils.
• October: Flowering. Enjoy the apricot scent.
• November: Mulch over the roots. Move pots to a sheltered spot.
• December: In severe frost, wrap in fleece or bring the pot indoors.

Did you know?

• The Chinese city of Guilin is named after this plant: Guilin literally means ‘osmanthus forest’.
• In China the fragrant flowers are used to flavour tea, wine and sweet treats.
• The name Osmanthus comes from the Greek words osme (scent) and anthos (flower).