Lindera are native to my area and I have many. They get at least 12' tall and wide, and periodically I cut the largest stems back on the one in the shade garden and let the suckers fill in. That makes them a little smaller for a while. They do seed about and the seedlings are not easy to pull.

Thanks... didn't know that the lindera spread - seems like it's pretty aggressive.

I don’t grow Cephalanthus, but the wild ones I have seen in the seacoast area of NH have been over my head, perhaps 8’-10’. There is a selection, Sugar Shack, that is supposed to be smaller, something like 5’-6’. I don’t see them growing wild in my area which is colder than the seacoast, so they might be borderline hardy for you, depending on how cold your area gets. I keep meaning to try them along the edge of one of our sunnier wetland areas, but haven’t yet, so I can’t be sure about their hardiness.

I do grow Lindera benzoin, and it is borderline hardy here, having gotten killed back two years in the almost 10 years it has been growing here. They are fine to -17F, but somewhere between there and -22F they get cold damage and in those cold years I have to do quite a bit of pruning to remove dead branches. I haven’t ever seen one growing wild in this area, though where I grew up in the Great Lakes area I saw them on the higher parts of wooded flood plains.

A few nurseries sell them in our region so I figure they must be cold hardy... for what it's worth, Dave's Garden states that they are hardy to -34.5 C - I don't recall it ever getting that cold here...