The spring-flowering spirea species include the birchleaf spirea Spiraea betulifolia and bridalwreath spirea Spiraea prunifolia , which thrive in USDA zones 5 through 8, depending on the cultivar, while Nippon spirea Spiraea nipponica and Vanhoutte spirea Spiraea vanhouttei are hardy down to USDA zone 3. If you live in a warmer climate, consider planting the 3- to 5-foot-tall and equally wide threelobe spirea Spiraea trilobata , hardy in USDA zones 3 through 9, according to the North Carolina Extension.
Summer-flowering spireas include the native white- to pink-flowering meadowsweet Spiraea alba , hardy in USDA zones 3 through 7, and Billard's spirea Spiraea billardii and Japanese spirea Spiraea x japonica , suitable for USDA zone 3 through 8 gardens. The Clemson Cooperative Extension warns that Japanese spirea, a hybrid of Spiraea trilobata and Spiraea cantoniensis, and its cultivars are invasive in the Southeastern U.
Spireas flower in spring or summer, depending on the species and cultivar, so pruning time varies according to the bloom time. Prune spring-flowering shrubs immediately after the flowers fade, so the plant has time to recover and produce new buds in summer and fall for spring flowers, according to Professor John Ball, SDSU Extension Forestry Specialist.
You can wait to prune summer flowering shrubs until late winter or early spring, while they're still dormant, as the flower buds are formed in spring for summer flowers. Before you begin, take time to examine the shrub and determine if it needs deadheading and trimming, renewal or rejuvenation. Old canes may still produce foliage, but they prevent growth and block the sun from reaching the lower branches. Cut them off at the base of the plant. In the fall or late-winter, prune the spirea again.
This trim is more aggressive than the spring-time one. Remove all dead branches, old foliage, and old blooms. Look for dead spots and places where the undergrowth is struggling. With many large shrubs, the growth and flowering are all at the top, and underneath is a mess of dead or foliage-less branches.
Cut it back far to stimulate new growth. Shape the spirea during this rejuvenation pruning, also. Creating a professional-looking, rounded shrub is easy. Tie a rope around the middle of the spirea. Using sharp hedge shears, cut straight across the top of the bush. When the rope is removed, the bush pops back nicely rounded.
Prune the bush throughout the year as needed. Here are some supplies and tools we find essential in our everyday work in the garden. We may receive a commission from sales referred by our links; however, we have carefully selected these products for their usefulness and quality. Best Planter Caddies for Healthier Plants. Pruning Spirea By: Jim Childs Check out this no-fail advice for pruning spirea to get more flowers and keep its habit tidy throughout the season.
Prune spirea to encourage a rebloom To get more flowers later into summer, snip off the spent heads as they fade. Prune to make tight mounds If you like a dense, structured look, prune just as new leaves start to show in spring. Japanese spirea varieties require tip pruning at this time, or in early spring. Trim a spirea into a round shape by first tightening some jute or rope around the center of the plant. Trim across the top of the plant, then remove the rope to reveal a round shape.
Trim any remaining growth that sticks out beyond the basic orb shape. Spireas thrive when trimmed regularly. Leaving them untrimmed from winter until the leaves have grown in can actually make the plant look less healthy, with thick growth in some areas and sparse growth in others.
To prevent this from happening, trim the spirea at least twice a year. Use clean, sharp shears to prevent damage or the spread of disease during pruning.
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