I have a semi-circular bed in the corner of our yard which has a cranberry viburnum in the corner with concentric rings of various plants: front silver lirope, then pink Songbird columbine, then Siberian iris. Behind the iris are the bulbs: daffs and muscari which are all that is in bloom now. When they're done I'd like to either plant something OVER them or BEHIND them, or both, which will cover the dead foliage and the bare space they leave behind all summer. By the way, this area is very shady. I thought of planting tall coleus over them and tall astilbe (white and pink) behind them. What do you think of this idea?(I tried daylilies but there just wasn't enough sunlight and they flopped.) I'm open to any other ideas too. (I don't have too much space behind the bulbs and it is under the boughs of the viburnum.)