Snowball Viburnum (Boule de Neige): Planting, Care and Cut Stems

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Boule de neige — French for “snowball” — is a decorative viburnum that is covered in dozens of white globe-shaped flower heads in late May. The shrub is undemanding, long-lived and looks lovely both in the garden and in a vase. Here is how to plant, care for, prune and propagate snowball viburnum, and how to cut stems for a bouquet so they last longer.

How snowball viburnum differs from wild guelder rose

Boule de neige is a garden form of guelder rose (Viburnum opulus 'Roseum'). Wild guelder rose has flat flower heads: small fertile flowers in the centre and large sterile ones around the edge. In the snowball form all flowers are sterile and gathered into round heads 10–15 cm across, so the shrub produces no berries or seed. The heads open lime green, turn white and may blush pink at the end of flowering. The shrub reaches 3–4 m, and its leaves turn crimson in autumn.

When and where to plant

• Timing: in spring before bud break or in autumn, from September to mid-October. Container plants can go in all season if watered.
• Position: sun or part shade; flowering is more profuse in sun. It likes moisture, so spots near water suit it, but avoid waterlogging.
• Soil: fertile, loose, slightly acidic to neutral.
• Planting hole: about 50×50 cm with compost. Set the root collar 3–5 cm deep, water well and mulch.

Care: watering and feeding

Water young shrubs weekly, more often in heat; mature ones during drought and flowering. Feed with nitrogen fertiliser or compost in spring and a balanced fertiliser in early summer; stop nitrogen from August so shoots ripen before winter. Bark or compost mulch keeps moisture in and protects the roots. Snowball viburnum is hardy and overwinters in Ukraine without cover.

View full-size photoSnowball viburnum produces large white globe-shaped flower heads in late May.

How to prune

Next year’s flower buds form in summer on this year’s shoots, so do formative pruning right after flowering: shorten stray branches and remove crowding ones. Remove dead, broken and diseased wood in early spring. Every few years cut some old stems to the base to rejuvenate the shrub.

How to propagate

Snowball viburnum sets no seed, so it is propagated vegetatively:

• Layering — the easiest: in spring bend a low branch to the ground, cover it with soil and separate the rooted plant a year later.
• Softwood cuttings — in June take 10–12 cm cuttings with 2–3 nodes and root them under cover in moist compost.
• Division — separate young suckers in spring or autumn.

Pests: viburnum leaf beetle and aphids

The main enemy is the viburnum leaf beetle: in spring its larvae skeletonise the leaves. Pick them off or spray with an insecticide, and in winter prune out twigs carrying egg clusters. Black aphids curl young leaves — spray with soapy water or an insecticide. Treat before or after flowering.

Snowball viburnum in a vase

Cut stems early in the morning once the globes have turned white. Split the stem ends by 3–5 cm, strip most of the leaves and put them straight into cool water. Cut snowball viburnum lasts about a week. It looks lovely with peonies, peony-shaped roses and lilac. Florists also use imported green viburnum globes out of season.

View full-size photoTo make snowball viburnum last longer in a vase, split the stem ends and remove most leaves.

More bouquet flowers are in our florist’s glossary.

FAQ

Why is my snowball viburnum not flowering?

Usually deep shade, pruning in spring or autumn (which removes flower buds), too much nitrogen or a young plant: it typically starts flowering in its 2nd–3rd year.

Does snowball viburnum have berries?

No, all its flowers are sterile, so it produces no berries or seed.

How long does it last in a vase?

About a week if you split the stems and put them in cool water right after cutting.

Author: Maria Svitlovir

Graduated from Taras Shevchenko National University of Kyiv, Institute of Biology and Medicine (2001). BSc in Biology, MSc in Horticulture. Writes about plants, works at a garden centre selecting and repotting plants, and contributes to plant reference guides.

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