Haven't grown it myself, but here's a nice planting in the area (photo taken 5/19/17). My impression is the species dislikes very dry conditions.

Wow, that is an impressive specimen! It looks wider than tall and is consuming some real estate. Any idea what the soil is like?

Not sure on the soil type, but the local area is generally well drained, and the yard is irrigated. There's also an estate nearby that has an older, taller specimen (planted many years ago) next to a woodlot, and I've noticed a few volunteers growing in the moister parts of that woods. Probably has the potential to become somewhat invasive with the right conditions.

Thanks, Arbordave. I too have read it can be invasive, but with our sandy soils and being at the upper limit of its cold tolerance, I’m not too worried about that.

My plan at this moment is to move ‘Seneca’ to an area that is irrigated and leave the seedlings where they are. It will be interesting to see how they do without any intervention. I suspect it will be a short experiment.

I didn't see this thread when it was new. I planted two very small V. Sieboldii here in Indy in 1978. Soils are well drained. Too well drained for some things. Both were planted is a somewhat wooded area. One died in our '88 drought. The remaining specimen is now in virtually full shade as a mature red oak on one side and a red oak sapling on the other side continued to grow over the years. That specimen is now probably 18' tall and 8-10' wide. It is healthy, but I have to keep an eye on it during dry periods. The more extreme dry periods have caused some die-back when I didn't begin watering soon enough, but it has survived and looks great in most years. It doesn't bloom every year and probably not even every other year. I don't remember that it has ever had fruit, but may have just forgotten. I don't seem to have a photo of the shrub other than the foliage in 2011, the only year it had fall color.

I have a question about my Sieboldii.

No sign of this being invasive! For the first time ever, it has produced either a sprout from a root or a seedling coming up inside the drip line. This is about 5" tall with only four leaves so far. We had amazing rains spread out fairly evenly throughout the spring this year. Most plants have done very well this year. I haven't investigated yet to see if this is a seedling I can move. Does anyone know if a Sieboldii will sometimes send up shoots from the roots in its old age? Thanks.

My post immediately above mentioned a sprout or seedling. I looked more closely last week and discovered it's a layered branch. I'll try to relocate the new plant this week.