Q: I love ornamental grasses and have mixed many among my perennials, with dull results. How can I make this combination come alive? — Ray Pasco, Redmond, Wash.
A: Don’t hesitate to remove or relocate any grasses that fail to excite you. Group those of similar heights together, pairing them with perennials of similar stature and vigor. Now is a good time to plant perennial companions, but wait until next spring to transplant or divide your grasses. Think about what it was that attracted you to grasses in the first place. Was it the wildness of prairies and meadows? If so, you can be a purist and mix native grasses like big and little bluestem, Indian grass, and prairie dropseed with colorful American perennials — liatris, bee balm, black-eyed Susan, purple coneflower, and aster. Or take an eclectic approach, using midheight exotic grasses to bring a variety of textures, colors, and forms to your flower border. Blue oat grass, purple moor grass, and feather reed grass (Calamagrostis spp.) mingle beautifully with Maltese cross, Phlox paniculata, veronica, yarrow, and the taller sedums. If it was the almost tropical look of the larger, bolder grasses like Miscanthus or switchgrass that first captivated you, mix in some voluptuous hardy hibiscus, tall daylilies, cannas, and annuals like Tithonia and cleome. In light shade, include the kinds of grasses that give Japanese-style gardens some of their quiet elegance. Tufted hair grass, autumn moor grass, and Hakonechloa macra ‘Aure-ola’ make serene statements among hostas and ferns.