Rock Cress Cascading (Aubrieta Hybrida Superbissima Cascade Purple) – The perfect ground cover plant seed is not easy to find, but this one is bursting will color. Plant Aubrieta seeds on flat ground to make a beautiful mat of purple blooms or plant along the edge of a rock or concrete wall and let it cascade over the edge. Rock cress can even be planted in hanging baskets or containers as long as the ground cover seeds are thinly planted in a sunny location.