Prague viburnum

Prague viburnum: how do you recognise it?

Habit

Dense, upright shrub, 2–3 m high and wide, with many branches.

Leaves

Leathery and glossy dark green, oblong, up to about 10 cm long, paler underneath. In mild winters it keeps almost all its leaves.

Buds

Pink buds, visible months before the flowers open.

Flowers

Flat heads of creamy-white flowers in May–June.

Roots

Shallow and fibrous: best moved in spring or autumn.

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

Why grow it?

• Stays largely green in winter: a dense, calm backdrop for the border.
• Creamy-white flower heads in May and June, a good food source for bees.
• Tough and easy: grows in sun, half shade and shade, on sandy, loamy or clay soil.
• Very useful as an informal hedge or a screen against prying eyes, but also as a single specimen.
• Little work: a light prune after flowering is enough.

Prague viburnum: where does it grow best?

• Sun, half shade or shade; it flowers best in sun.
• Any well-drained garden soil: sand, loam or clay, acid to chalky. Humus-rich and moisture-retentive soil is best.
• Normal moisture; it tolerates dry spells once established, but not wet feet for long.
• Sheltered from cold, dry east winds in winter, which can shrivel the leaves.
• Allow 2–3 m per plant as a specimen; for a hedge, plant every 1.2–1.5 m.

Light

Sun, partial shade and shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Normal

Size

3 m tall, 3 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Hydrangea: Flowers later, in summer, in the same half shade.
• Lady’s mantle: A soft, yellow edging in front of the shrub.
• Hosta: Large leaves beneath the shrub in the shade.
• Daffodil: Flowers in March–April beneath the shrub, before it blooms.

Prague viburnum: when and how to plant it?

Plant in April–May and September–October.

1. Plant in April–May or in September–October. In autumn it roots fastest in the still warm, moist soil.
2. Dig a hole twice as wide as the root ball and loosen the bottom.
3. Mix the soil you dug out with a few spadefuls of compost.
4. Set the plant at the same depth as in its pot, backfill and firm the soil well.
5. Water thoroughly straight away and keep the soil moist during the first year.
6. Spread a 5–8 cm layer of mulch (leaf mould or wood chips) around the base, keeping it clear of the stem.

Care

Water

In the first year, weekly in dry weather. After that only in long dry spells; even in a dry, frost-free winter an evergreen shrub appreciates the odd watering.

Feeding

In March–April, one spadeful of compost or organic fertiliser per shrub. Not too much, or it grows too lushly.

Mulching

A layer of leaf mould or bark in spring keeps the soil moist and suppresses weeds.

Spent flowers

There is nothing you have to remove. For a tidier shrub, cut off the faded heads after flowering.

Tip: Plant it in a sheltered spot away from harsh east winds and the leaves will stay handsome through winter. Prune only after flowering, because the buds are already there in winter.

Prague viburnum: when to prune it?

Pruning months: June.

When: After flowering, in June. It needs little pruning.

How:

• Shorten branches that are too long or stick out back to a side shoot or a bud to keep the shape.
• Remove dead, damaged or crossing branches completely.
• Clip a hedge once a year after flowering.
• To renew an oversized shrub, cut a few old branches back to near ground level in spring.

Caution: The flower buds are already on the branches in winter: prune in spring and you lose this year’s flowers.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Semi-ripe cuttings

In July–September: take 10 cm cuttings from young shoots, remove the lower leaves and insert them in sandy compost under plastic in a bright spot out of full sun. They root slowly, usually after a few weeks to a few months.

Layering

In spring, bend a low branch down to the ground, cover a section with soil and pin it in place. Separate it after a year and replant.

Prague viburnum: how does it get through the winter?

Hardy to −25 °C.

• Hardy down to about −25 °C: in Belgian winters protection is usually not needed.
• In severe frost the leaves may curl up or drop. That is not a disaster: it leafs out again in spring.
• Give young plants a thick layer of mulch around the base in the first winters and a screen against cold east winds.

Diseases and pests

• Viburnum leaf beetle: Small holes in the leaves from May to July, made by the beetles and their larvae. Pick off the larvae and cut out twigs with rows of eggs (small pits in the bark) in winter. A healthy, well-watered shrub recovers easily.
• Aphids: Dense clusters on young shoots in May–June. Wash them off with water or let the ladybirds do the work.
• Frost damage: Brown, curled leaves after severe frost or dry east winds. Wait until April to tidy up and water in spring.
• Root rot: In waterlogged, compacted soil the shrub turns yellow and declines. Make sure the soil drains well and avoid standing water.

Through the year

• March: Apply compost. Check for frost damage, but do not prune yet.
• April: Plant and mulch. Remove dead wood.
• May: Plant. First creamy-white flower heads. Water in dry weather.
• June: Flowering. Prune after flowering and clip a hedge into shape.
• July: Take semi-ripe cuttings. Water in dry weather.
• August: Take cuttings. Watch for leaf beetles.
• September: Plant: autumn is ideal.
• October: Plant and mulch.
• December: Rest. Water now and then in dry, frost-free weather.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• Despite the name ‘snowball’, it does not have round balls of flowers: the flower heads are flat. The true snowball bush is a different shrub, Viburnum opulus ‘Roseum’.
• It is a hybrid of two Chinese species, Viburnum rhytidophyllum and V. utile. The species name refers to Prague.
• It belongs to the genus Viburnum, like the guelder rose (Viburnum opulus) and laurustinus (Viburnum tinus).