UPDATE: The monster got out of control and we decided to get rid of it (no easy task!) It was taking over the Rose of Sharon bushes and the Catmint. It would be great ALONE in a large, contained area, but you won't want to plant it in with other plants unless you're ready to let them be choked out.
Blue Dune Lyme Grass
We call BLUE DUNE LYME GRASS the Blue Dune Monster. This is a vigorous, attractive plant that will quickly fill in a large area. We underestimated how big it would get and would almost label it invasive, but we like it well enough that we plan to move some other plants out of its way this fall so it can fill in the flowerbed behind the house. We especially like it for its contrasting blue-gray color. And the fact that a weed wouldn't stand a chance in its shadow.