How to Prune Shirobana Spirea
Shirobana spiraea (Spiraea japonica "Shirobana"), also known as peppermint spiraea, is a flowering shrub that is commonly grown as a low hedge. Although pruning keeps the Shirobana to the size you desire, it is capable of growing to 5 feet tall with a 4-foot spread.
The Shirobana spiraea takes its nickname from the fact that both pink and white flowers are produced on the same shrub, giving it a peppermint-type colouring. Shirobana spiraea requires minimal pruning when grown within zones 4 through 8 on the U.S. Department of Agriculture Hardiness Zone Map.
Remove dead flowers in late fall or early winter.
Prune the Shirobana spiraea in early spring by cutting off all dead wood, to its point of origin. If the plant is overgrown you can safely cut it back to within 6 inches of the soil.
Shape the Shirobana spiraea in early spring. Cut long stems that protrude from the bush back to the main area of the plant. For a formal appearance, shear the top and sides to the shape desired.