We've transplanted a few of the seedlings. They're true to their parent in terms of color, but the parents seems like a double bloom and the children seem like single bloom
If you want a hedge, this seems like a good option
Cons:
Seeds! So many seeds. Each of its hundreds (thousands?) of flowers will produce 10+ seeds. They all don't germinate, but it's a numbers game. If you want to avoid pulling volunteers up you're best off pulling the seed pods off the plant before they open on their own
I pulled ~2 gallons of seed pods off a week prior to this picture. My wife dumped them in the compost, so no epic 5+ gallon photo 😭
Some of those are looking pretty ripe! I like to try to get a block of time to go after the bush in long chunks, but that's not always possible. How big is yours / how many do you have? We have two. One is tiny (about 3 feet tall), but the other is pretty big/bushy (10 feet tall or so). The big one takes an hour or two to pull all the seed pods off...
I have just one (really small garden). It's fairly big though, I'd guess around 10 feet high. I couldn't reach the top so there are still some pods there. Picture from the end of August for reference:
That's a very nice looking area. Your Roe of Sharon is much better pruned than ours - we more or less let it to wild and trim the sides if it's getting unruley. I also suspect yours is more mature based on the size of the trunk towards the top. Ours is still flexible enough that I can grab an offshoot and pull the whole branch it's connected to down.
Looking at yours, and thinking about our 3' tall one we grew from seed, I think our original plant is really a collection of a bunch of individual plants that were grown in a common pot.