It appears (to me) that there are two generic listings for this plant - H. anomala and H. petiolaris. I am not sure which is the more accepted name so am reluctant to propose a merge. Perhaps one of the admins can help out?

They can't be merged, Deb. They're two separate species.

OK, guess I need to do some research to figure out which one I actually have then. I have linked to both entries in different ways. Hmmm. Good evening project!

I am sure having trouble trying to figure out how to differentiate between the two - I think I'll post some of my pics over in the ID forum and see if anyone there can help me out.

Deb, take a look at this Missouri Botanical Garden description of Hydrangea anomala subsp. petiolaris, specifically the paragraph which begins

Subsp. petiolaris (formerly known as Hydrangea petiolaris)...

where they describe some differences.

Ah, thanks Evan. From reading that post, I'm fairly certain I have H. anomala although next spring I should be able to count the stamens for a more definitive ID - less than 10 for anomala and more than 10 for petiolaris. Since I keep the shrub pruned to the ridge of our barn, no telling how big it would eventually get, although I'm fairly certain it would attempt to conquer the world if given a chance! My flower clusters also seem to match better the anomala description, although I take exception with the "non-showy" characterization (but that's just me). Meanwhile, I'll mark my ID thread as solved. Thanks so much.

I'm glad it helped.

Aha - a simple question led to figuring out just what exactly I have, and then learning how to edit tags on multi-plant photos. Excellent! Thanks Evan and Zuzu for steering me in the right direction.