Can Spirea Be Pruned in Spring?

About Spirea

• There are two main groups of spirea shrubs; those with long, arching stems that produce white flowers in early to midspring, and those with upright, compact growth that bloom from summer to fall with umbrels of flowers that may be white, pink, red or purple. Plants in the spring-flowering group include bridal wreath or Vanhoutte spirea (Spiraea x vanhouttei), suitable for U.S. Department of Agriculture plant hardiness zones 3 through 8; baby's breath spirea (Spiraea thunbergii), hardy in USDA zones 4 through 8; and popcorn spirea (Spirea prunifolia), sometimes also called bridal wreath, which has double flowers and grows in USDA zones 5 through 9. Japanese spirea (Spiraea japonica) and bumalda spirea (Spiraea bumalda), which have hundreds of named cultivars between them, are the two main summer-flowering species.

Pruning Spring-Flowering Spireas

• Keep the pruning shears in the shed and just enjoy the wealth of flowers that bridal wreath and baby's breath spirea varieties produce in the spring. Once flowers fade -- they tend to turn brown after a couple weeks of profuse bloom -- it's time to prune. Resist the urge to quickly shear your plant into a neat dome.This may look nice in the short run, but spoils the waterfall effect of its branches when it flowers next spring. Instead of cutting off the tips of all the branches, reach into the center of the shrub and remove one-third of the longest, oldest canes each year. This reduces the size of the plant, allows for more light and air, and rejuvenates growth from the base of the plant, while retaining its natural shape. If it is still too big, you can shorten canes back to a side shoot.

Pruning Summer-Flowering Spireas

• Spireas that bloom in summer produce flowers on the current season's growth. Though you don't have to prune them every year if you like their size and they're blooming well, late winter to early spring is prime time for pruning these shrubs if you want maximum flowering. Varieties that are known for colorful foliage can be cut to 3 or 4 inches from the ground each year for the freshest looking growth. Otherwise, thin one-third of the oldest canes back to the ground each year. and shorten as you would spring-flowering spirea. Deadheading, cutting off old flowers, can prompt a new round of bloom in summer flowering spirea, and prevents spread of the plant by seed. Japanese spirea is considered invasive in some states.

Considerations

• Timing isn't important when you see dead or broken branches on your spirea -- cut them as soon as you notice them. Whenever you prune, use tools that are sharp and clean. Tools should be sterilized with household antiseptic cleaner and wiped dry before you use them, as well as between cuts when plants show signs of disease. Either type of spirea can be cut back to the ground in late winter or early spring when they aren't performing well, are oversized or have been mispruned in the past.