Snowball viburnum is a white blooming varietal of viburnum that produces round-shaped flower heads made up of multiple blooms that resemble snowballs. Snowball viburnum blooms in May and unlike most viburnums does not produce berries after bloom. It grows up to 20 feet in height at maturity and though it does not require regular heavy pruning, it might need to be pruned every few years to control its shape or size. It is often used as hedging or specimen plantings and can be formed into tree form by topiary pruning.
Prune your snowball viburnum lightly throughout the growing season to harvest flowers and remove any dying, damaged or diseased foliage and branches. Use clean, sharp secateurs and place all cuts at least a quarter inch above a leaf node or bud. Remove damage or diseased branches down to the point and at least a a half inch past where you reach healthy wood.
Hard prune your snowball viburnum for shape and size every few years or as needed. Remove up to one-third of the shrub's interior and perimeter branching but no more in order to reduce stress on the plant. Hard prune only in the late spring or early summer immediately after blooming to avoid removal of the next season's flower buds. Prune lightly to maintain the shrub's natural roundish shape or shear and cut the branch tips back more dramatically to create hedging or a trained-tree form.
Restore a damaged, misshapen or badly neglected shrub by pruning weak or overcrowded branches down to the crown of the plant. Place cuts evenly throughout the shrub to restore a natural globe shape and ensure good sunlight penetration and fresh air flow through the shrub. Pull each off cut out of the shrub and inspect your work before making the next cut to give a professional and natural looking result.