Certified GKH Gardening Expert
There are numerous perennial plantings that work well together. The main thing to keep in mind is the growing conditions of the plants you choose. Those that complement one another will shade the same or similar growing requirements. So, for instance, full sun plants will need to be with other full sun plants (black-eyed susan, coneflower, liatris, lambs ear), and shade plants in the shade (like hostas, ferns, violets, hellebore).