Yes. You have planted a quickly developing, tall arching vase - much greater in height and spread than it has become so far. The only problem with the suggested replacement - which is presumably the same one that has been on the market here - is that it has inferior coloring, fades badly during summer. What is needed next is the introduction of a selection with the same narrow habit but with a good, persistent and dark leaf color.

In reply to your question about bloom, yes, you would lose flowers by pruning now. Elder flowers on old wood so if you prune do it immediately after flowering. But as the others have said this plant isn't amenable to growing the way you want. The ones growing around here end up about 8 feet tall and wider than that. Very old unpruned specimens develop into small gnarly trees.

Black Tower hasn't performed any worse for me than the others in sun. They all fade eventually.

Thanks. I guess I was just tempted by the color and the lacy leaves. :( I'll see if any nurseries have Black Tower. If I can get it, I'll move this one elsewhere. The nurseries around here tend to have same old, same old; but maybe I can find one when I am travelling out of town. That's where I found this one.

If you wait a bit you might be able to find Strait-laced.