Celtic Dancer is a medium green rippled vase shaped Hosta. Since you've already got a lot of variegation there, a green architectural plant might work well.

You can cut that Butterfly bush to about 6 inches from the ground early each spring and it will bounce right back to give you full blooms each year. That would keep it in perspective with the rest of the garden. I love the pond. I would like to do one, but I have lots of other projects in the works.

Steve