Answer: Spireas can be renewed over a three year time frame by selective pruning. Trim out one third of the oldest stems by cutting them off at the ground. Then next spring, right after it blooms, trim out half of the remaining original stems by cutting them off short at the ground. In year three, right after it blooms, trim out the remaining old stems. After that, each year remove just a few of the oldest stems. This will allow the shrub to renew itself on an ongoing basis and stay vigorous.
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