I have acid fine sandy loam and had this for a few years before I ended up shovel pruning it. It had a lot of dieback each winter, even though it spent much of the winter buried in snow, and never grew enough during the growing season to catch up to the losses. So it got smaller every year over several years until I got rid of it.

I know that full sized Itea virginiana is growing within 1/2 hour or so of here, so I wonder if 'Little Henry' has a more southern provenance and isn't quite as hardy. Mine was growing in a well-mulched bed in part sun with high bush blueberries, Yaku Rhodoendrons, Cornus alternifolia/pagoda dogwood and Kalmia latifolia/mountain laurel, so it should have been happy.

Thx nhbabs, glad for the foreknowledge. You may be right about provenance, Bluestone lists it as Zone 5. Sounds as if you're on the cool end of that and I'm on the higher. If I can't find anything else that seems right I may give it a try anyway.