Bridal wreath spireas can be pruned after flowering. Japanese and bumald spireas must be pruned in early spring for best flowering. Dead, broken and diseased branches can be removed at any time.
Bridal wreath spireas can be deadheaded after flowering to produce a second flowering before pruning. Bridal wreath bushes can tolerate severe pruning if necessary and return to full growth and flowering. They should be pruned yearly to maintain height and shape.
Make sure to identified what subspecies of bridal wreath so that the year's flowers are not lost. The classic bridal wreath Vanhoutte spirea (S. vanhouttei) grows to approximately 10 feet tall and 20 feet wide. This is the variety to prune after flowering. The smaller bumald spirea (S. bumalda) and medium-sized Japanese spirea (S. japonica) should be pruned in the early spring before buds begin to form.
In addition, bridal wreath bushes should be composted and mulched each year in early spring before flowering. Simply lay down a layer of compost underneath the bush from the trunk to the outer branches of the bush. Then place a two inch layer of mulch over the compost to retain moisture and prevent weeds. Water the bush if rainfall drops below 1 inch per week.