Rooting cuttings at this time of year is always problematic for me. I've had much better success with early green cuttings or late woody cuttings. Mid-season never seem to work here in KY.
I had to chuckle, your statement of sterile seeds being unable to germinate. All I could think of was Jurassic Park and nature always finds a way. Now, I have the hankering to go watch that movie.
lol - nature does usually end up winning out in the end, doesn't it.