Answer: If it has already leafed out, it is a bit late to shear it as you risk removing the main bloom display. If it has not leafed out yet, go ahead and cut it back by a half to two thirds. Or, you could shear lightly right after it blooms. Typically you would cut this shrub back by about half in very early spring before it starts to grow. This encourages vigorous new growth and better blooming. Then after bloom, you would trim it lightly (shear) to remove the faded flowers and tidy it up. I hope this helps.
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