I don't know much other than it is a popular bonsai subject. But here are a couple of fact sheets that should shed more light:

https://plants.ces.ncsu.edu/plants/serissa-japonica/

https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=302224&isprofile=0&;

Lots of bonsai websites discuss it as well.

Id read both of those and they actually go against what the nursery says.

They are only 100 miles away or so and it’s recommended as a very small evergreen hedge or front of the border plant.

I hope it actually is evergreen. I’ll do a trial with the two I ordered.

I‘ll either plant them with afternoon only sun or all day sun intermingled with some climbing roses that have no low foliage