The Chinese Snowball Viburnum
With really large rounded white flowers Viburnum macrocephalum is commonly called the Chinese snowball tree. It makes a magnificent specimen in the garden when in full flower.
Viburnum macrocephalum Fast Facts
- The flowers can get to 10 – 20 cm across (4 – 8 inches) and the plant itself can easily reach 4 metres (12ft+) in height over time.
- This a semi-evergreen to deciduous tree depending on the climate. Deep green leaves with serrated leave margins.
- The large round flowers appear in spring and appear on the ends of the stems.
- The flowers are sterile, so propagation is from cuttings.
- This is a larger flowering plant than Viburnum opulus
How to Grow Viburnum macrocephalum
- Position
Best grown in climates with a temperate range from 10 to 35 C it will tolerate frosts however extreme cold and freezes will damage the plant. A position in full sun is best for good flowering and growth. - Soil
For best flowering and growth a humus rich well drained soil with a neutral to slightly acid pH is best. Consistently wet or waterlogged soils are not suitable. - Watering
Once established Viburnum macrocephalum is reasonably drought tolerant. If mulched, it may require no additional watering except in long dry periods over summer. When first planting water regularly through the first few summers. - Temperature Range
Although the Chinese Snowball trees will grow in colder climate zones it is best in cool temperate to warm temperate zone. It will not grow well in sub tropical to tropical zones due to both the heat and also the humidity which can cause fungal problems. - Fertilizer
The best time to fertilise is in spring just before you renew the mulch. Use a general purpose slow release type fertiliser, or in fertile soils try some aged cow manure.
PruneThe Chinese Snowball Viburnum
Kowing when and how to prune Viburnum macrocephalum is important. It flowers on old wood, so the time to prune is immediately after flowering.
A lot of pruning is not necessary, start by removing any dead wood, after a 3 – 4 years you can prune to shape if you wish.
You can prune back hard to around 30cm (1ft) from the ground but only do this if the plant need complete rejuvenation.
You could also selectively prune to a single leader, encouraging that stem to reach around 1m (3ft) or so little higher, before allowing the plant to bush out.
Prune large branches in winter.
Propagation Tips for Viburnum macrocephalum ‘Sterile’
As this is a sterile variety propagation is from cuttings. The best time to take cuttings for all Viburnums is in spring, although they can be taken in late summer as well.
- Take tip cuttings from non flowering stems or remove any flowers that are forming.
- Cuttings can be from 6 – 12 inches long.
- Remove the lower foliage for at least 1/2 the length of the cutting. Cut remaining leaves back by half.
- Use a liquid or powdered rooting hormone for best results
- Use a dibbler or stick to make a hole in the propagation mix so the cutting can be inserted without it being rubbed off.
- Use good quality potting mix or specialist propagating mix.
- Place the cutting in the hole and firm in around.
- Cuttings require humidity so use a cloche or plastic bag over the top to help maintain humidity.
- Mist spray every day for the first 14 days.
- Wait until signs of new growth appear and then remove the plants from th cloth or plastic bag.
- Keep the plants in light shade and water regularly
- Plant cuttings out in spring.
Summary Details
- Botanical Name – Viburnum macrocephalum ‘Sterile’
- Common Name – Chinese snowball, Chinese snowball viburnum
- Family Adoxaceae
- Origins – Asia
- Position – Full sun to part shade
- Soil – Humus rich and well drained. Neutral to slightly acidic pH
- Height – To around 3m (9ft) or taller.
- Width – Clump forming to around 2m plus.
- Flowers – Rounded large white
- Flowering Season – Spring
- Foliage – Mid green deciduous.
- Climate Zones – Cool Temperate to Warm Temperate