Also, if the babies would be very unreliable as good plants that bloom well, etc. are there any suggestions of a similar hardy shrub for color in the garden at about the same time or other varieties of rose of sharon (hibiscus) that are very hardy in pinks, purples etc.?

Thanks.

If you are getting seedlings it's not sterile. Sterile means there is no sexual reproduction. A friend used to get mostly the typical wild species flower color (strong pink) when growing Hibiscus syriacus seedlings in his nursery, although he may not have ever planted seeds of a blue one.

The Bailey nurseries web site does mention a blue selection they made coming from a block of blue seedlings, as though they took seed from a blue parent and got a bunch of blue ones. All you can do is grow yours on and see what color they are.

If it were me I would look at other properties in the area to see what looks good and seems to be doing well, to get ideas of other shrubs to try. Other properties including public gardens and other organized, labeled displays, as well as what I could see from the sidewalk.

When I was a child I grew Hibiscus syriacus "blue bird" in a warmer climate zone than I am now. The seedlings grew everywhere and were a real nuisance. So I think the "sterile" label is a selling point for others who have had that experience with other varieties. I was just wondering if others had pleasant results from seeds of blue satin (colour not so important as hardiness, flower opening etc.) I was afraid that if seeds were generally not viable from this plant, that the babies that did result would all be duds and get all the bad genes - short, slow growing, flowers not opening well, poor amount of flowers, etc.etc. Some posts on this site recommend specifically throwing out any resulting seedlings of blue satin so I'd like to know why they would recommend that. Also as the blue bird was not hardy in my current zone and the blue satins is, I'd like to be warned if the babies are not likely to be hardy so I don't have to face that heartbreak again when it dies after 5 years or so like it did with blue bird in my current location.