Fall is when I think of wild combos- like Tiffany said, large open, non-woody, areas become a tapestry of flower and foliage.
Otherwise, there is so much green between flowers, or when there ARE flowers they are in a swatch, I cannot think of a combo.
Maybe you could say our spring yard, since we don't use herbicide, is a nice combo, I like the tapestry of different shades of green plus some flowers (all non-native I suppose) before crabgrass takes over.
