I think you're right..the seeds don't have time to ripen enough to be viable. If they did, I still doubt they would come true to the parent. I grow P.v.'Northwind' and P.a.'Dewey Blue' and both reseed(I have perfect conditions for Switchgrass), but neither come true. I get some interesting variations, but not the real thing in either case.

I would be happy with some interesting variations!

For my garden I can get enough divisions off the main plant to fill my needs for clones(which is scheduled for the spring) but I was just wondering why the seed looks empty. I'm sure the birds would enjoy another place to peck around for a couple bites to eat, so fertile seed would be better. Interesting that your other cultivars self seed and you see some of the parent in the kids.

I'll have to take note this fall to see when the "dallas blues" bloom takes place and compare this to the other switchgrass. Maybe I can do some cross pollinating and get some good seed and some interesting results!