Caring for Spiraea X Vanjoutte
I've recently purchased a home with a hedge of what my neighbor told me was Spiraea x vanjoutte. It was growing out of control and hitting about 10feet tall. There are about 40plants, forming a hedge. My neighbor told me it was never pruned before, so I spent the weekend removing dead branches. The local garden shop suggested I cut one in every 3 branches, I did so but they also told me not to lower the height by pruning.
I was hoping to drop it to about 5feet, hopefully causing the bushes to bloom lower and thicker. Suggestions?