Paul: I am going to look at sieboldianas.You mentioned Elegans and I knew I had one in another spot that was labled.I also have Blue Mammoth there. All are 3 years old and have bluer leaves than my mystery. Its a rainy day here so I will wander thru the sieboldianas and come up with something.
This is my Elegans
Blue Mammoth
What back savers these giant varieties are. I risk broken bones on slopes to plant them,so the weed population stays at bay.