Sterilize the pruning shears by dipping the cutting blades in a chlorine solution containing 1 part chlorine to 9 parts water. Sterilizing the blades helps prevent the risk of spreading diseases to your Walter's viburnum while pruning.
Lift the branches of the plant and look for old wood and weak branches that have little fresh growth on the limbs. Hard-pruning involves removing much of the unproductive biomass on the plant.
Prune away the unproductive branches as close to the main stem as possible in early spring, before flushes of new growth appear on the plant. This type of hard pruning that removes old, unproductive branches forces the plant to focus new spring growth on the remaining branches.
Maintain the shape of the plant by hard-pruning new shoots and trimming away excessive growth on the main limbs of the plant after the plant blooms each spring. Wait until after the spring inflorescence to trim the plant since Walter's viburnums produce their flowers on the previous season's growth.