Pruning Snowball (Viburnum): how and when?

A shrub that requires little maintenance, is available in different sizes, has beautiful autumn colours and berries and beautiful, sometimes fragrant flowers? The Viburnum , or snowball, has it all! From Viburnum tinus to Guelder rose: we tell you when to prune the plant, and of course how to do it properly.

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Viburnum is not just one plant, but a whole genus of about 150 species. Among them are both evergreen species such as Viburnum tinus , as well as a number of deciduous species. The Guelder rose ( Viburnum opulus ) and woolly snowball ( Viburnum lantana ) are native here, but other popular species are the Japanese snowball ( Viburnum plicatum ) and the hybrid, scented snowball Viburnum x bodnantense .

Most viburnums do not need pruning, but they can tolerate it. There are three main reasons for pruning a snowball:

to get them back in shape

If all this is not necessary, leave the pruning shears. Also remember that snowballs bloom on old wood. If you were to prune every year, you would get few or no flowers and that is one of the most common pruning mistakes .

Viburnum is best pruned immediately after flowering. The flowering period varies per species. Winter flowering snowballs usually bloom from autumn to spring on bare branches. Other species (such as Guelder rose, Virburnum opulus ) bloom in late spring or early summer. If you want to prune a winter flowering snowball, such as Viburnum tinus or Viburnum x bodnantese , always do so immediately after flowering.

In late flowering species you can prune diseased and dead branches in March. After flowering you can prune overgrown shrubs, but prune no more than a fifth of the branches at a time.

When you need to prune your Viburnum or snowball, prune only a few of the thick main branches. Here's how to do it:

First choose the oldest, thickest main branch and cut it low to the ground, at a height of about 30 cm from the ground. Use a pruning saw for this.

Then step back and look at the shape of your snowball and determine which branch to remove next, and if you should. If you are happy with the shape, stop pruning and reassess your shrub the following year.

Tip

If the shape is out of balance, use a pruning shear to trim back a few offending side branches. After pruning, your shrub should not look pruned and should produce new growth lower down the shrub. Repeat this process next year.