Mar 02, Give it a good trim after it flowers in the spring by cutting back the tips of the stems to the top leaf bud. This removes the dead blossoms and also may trigger a second blooming and new leaf growth.
You can also shape the shrub at this time. More drastically cutting back spirea should occur in the fall or in late winter to early spring. Trim back overgrown spireas or those that produced sparse foliage on the lower stems severely in fall after the foliage begins to fall off, to keep the shrubs shaped and compact. Cut back each stem to within 8 to 12 inches of the ground.
In the same manner people ask what month should you trim bushes? The best time to rejuvenate large. Mar 30, Wondering when to prune spirea bushes? The best time to prune spirea is after the first flowering. For a spring-blooming cultivar, a good time will be in late spring. For a summer-blooming variety, this will be in mid-summer. During the spirea trim, Estimated Reading Time: 5 mins.