I had planted it originally in my small rain garden. But with it reaching 5+ feet, it was out of place in that tiny area. Moved it a few years later to a bigger space. I can prune the new stems in spring and get a shorter plant, but I don't always remember or have time to do that.
Perhaps if it never got watered, the plant might be shorter. It gets plenty of rainwater runoff!
This is actually a picture of the buds, not opened blooms. It does not have a showy flower (small and sort of a mauve color), but butterflies and other pollinators like it.
Thank you, Cal, Gardener, and Elizabeth for your comments. And to all who gave a thumbs-up. And an acorn, too!--thanks, Cal!