Sedum sarmentosum - Spreads rapidly, almost invasive. Good for extremely poor soils. Idea for planting along ditch. Stringy stonecrop, Sedum sarmentosum, is probably the fastest-growing sedum around -- at least in the cold-hardy species.
Dalmation Bellflower produces beautiful mounds of purple bell-shaped flowers from late spring through summer. Low-growing plant is perfect for adding color in front of other perennials. Grows only tall. Spreads Prefers full sun to partial shade.