Question
When and how should I prune my snowball viburnum in order to insure the most blooms in the spring?  Does it bloom on new wood?

Answer
Hello Virginia

Thank you for your question.

This particular viburnum blooms on old wood, i.e. the wood that grows this year will bear flowers next year.

The only attention your plant should need is dead heading as each bloom fades.

After the last flower has gone you need only take out any stems that are damaged or showing signs of disease.  It may also be advisable to remove any stems crossing each other and are rubbing the bark away.

If the plant is outgrowing its allotted space it may be better to move it rather than try to make it smaller by pruning as that could affect flowering for a year or two.