Korean spice viburnum

Korean spice viburnum: how do you recognise it?

Habit

Rounded, dense shrub 1.5–2 m tall and as wide, with stiff, upright stems.

Leaves

Broadly oval, 4–10 cm, dull green and softly downy, greyish beneath; often red in autumn.

Flowers

Domed clusters of 5–8 cm made up of small tubular flowers, in April and May, as the leaves unfold.

Colour

Pink to red buds opening to white or very pale pink flowers.

Scent

Sweet and spicy, often compared to cloves.

Fruit

A few small berries, first red and later black; not showy.

Flowering: April–May · Plants: March–April and October–November · Pruning: June

Why grow it?

• One of the most fragrant spring shrubs: you can smell it from afar.
• Lovely at every stage: first pink buds, then white flowers.
• Compact and slow-growing, so it also suits a small garden.
• The early flowers attract bees and bumblebees.
• The leaves often turn red to purplish red in autumn.

Korean spice viburnum: where does it grow best?

• Sun or partial shade; it flowers most freely in sun.
• Ordinary garden soil: sandy, loamy or clay, acid to chalky.
• Moisture-retentive but well-drained; it dislikes wet feet and long droughts.
• A sheltered spot by a patio, path or window, where you can best enjoy the scent.
• Allow 1.5–2 m per plant.

Light

Sun and partial shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Normal

Size

1.5 m tall, 1.5 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Daffodil: Yellow flowers at its feet, just before or alongside the viburnum.
• Tulip: Flowers in April and May, in the same sunny border.
• Lenten rose: An early bloomer for the partial shade beneath the shrub.
• Forget-me-not: A haze of small blue flowers around the white blooms.

Korean spice viburnum: when and how to plant it?

Plant in March–April and October–November.

1. Plant in March–April or October–November, when the soil is neither frozen nor waterlogged.
2. Dig a hole twice as wide as the root ball and mix in a few spadefuls of compost.
3. Set the plant at the same depth as it was in the pot. On a grafted plant, the graft union should stay just above the soil.
4. Keep 1.5–2 m from other shrubs.
5. Water in thoroughly straight away, even if it is raining.
6. Spread a layer of compost or wood chips around the base.

Care

Watering

Weekly in dry spells in the first year. After that only in long dry periods.

Feeding

In March, a layer of compost or a little organic feed for flowering shrubs.

Mulching

A layer of compost or leaf mould keeps the soil moist and feeds the shrub.

Suckers

Remove rootstock shoots as soon as you see them: they have different leaves and grow more vigorously.

Space

Let it grow in its natural, rounded shape; clipping it into shape costs flowers.

Tip: Plant it by a patio, path or window so you can make the most of its scent in April and May. Only prune straight after flowering, and as little as possible.

Korean spice viburnum: when to prune it?

Pruning months: June.

When: Hardly ever needed. If you do prune, do it in June, straight after flowering.

How:

• Remove dead, damaged and crossing stems.
• Shorten a few over-long stems to keep the rounded shape.
• On an old, bare shrub, take out one or two old stems at the base every few years.

Caution: Do not prune in winter or spring: you would remove the flower buds, which form the previous year.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Softwood cuttings

In June–July: 8–10 cm cuttings from young shoots, lower leaves removed, in moist cutting compost under plastic.

Layering

In spring, bend a low stem to the ground, lightly wound the bark and peg it down under some soil. Sever after a year.

Korean spice viburnum: how does it get through the winter?

Hardy to −25 °C.

• Hardy to about −25 °C: no protection needed in Belgian gardens.
• The flower buds sit ready at the stem tips all winter.
• A late frost in April can turn the buds or open flowers brown; cover a young plant with fleece for the night.

Diseases and pests

• Suckers: Rootstock shoots on a grafted plant, with larger, different leaves. Cut or pull them off as low as possible.
• Aphids: Curled young leaves in spring. Ladybirds and birds usually deal with them; otherwise spray them off with water.
• Brown flowers: Caused by late frost. A sheltered spot helps; the shrub itself does not suffer.
• No flowers: Usually pruned too late or too much shade. Only prune in June and give it more light.

Through the year

• March: Plant. Give compost.
• April: The pink buds colour up and the first flowers open. Watch for aphids.
• May: Full flower with a strong scent. Bees and bumblebees.
• June: Light pruning after flowering. Take softwood cuttings.
• July: Water in dry spells.
• August: Water in dry spells. New flower buds are forming.
• October: Autumn colour. Plant.
• November: Plant.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• It is named after William Richard Carles, a British diplomat in Korea who collected plants there in the late 19th century.
• It is a parent of several fragrant garden hybrids, such as Viburnum × burkwoodii and Viburnum × juddii.
• The flower buds form as early as the previous summer and overwinter at the stem tips.