Although I made a disastrous combination with my tulips, spring beauties and hepatica, I have had success using other natives—ferns in particular—to mask the dying foliage of non-native spring bulbs. Native ferns such as ostrich (Matteuccia struthiopteris) and sensitive (Onoclea sensibilis) also do double duty as camouflage in a garden with part sun, while native woodland perennials such as mayapple (Podophyllum peltatum) and Solomon's seal (Polygonatum biflorum) can serve a similar function in a shady garden.
Another camouflage trick in the combination garden is to use natives in areas that are notoriously tough on many cultivated varieties: the dry shade under trees with dense canopies, for example. In such conditions, you'll save yourself a struggle by using dry-shade-adapted natives around the base of the tree, such as barren strawberry (Waldsteinia fragarioides), zigzag goldenrod (Solidago flexicaulis), woodland sunflower (Helianthus divaricatus), black snakeroot (Actaea simplex Atropurpurea Group syn. Cimicifuga racemosa), Christmas fern and (Polystichum acrostichoides), for instance. Reserve the thirstier non-natives for the areas outside the canopy, where they'll get the benefit of rainfall.
Competing for space
Another consideration is plant competition. Whether the plant is native or non-native, be sure to take its “spreadability” into account when planning placement. I've had more than one native blazing star (Liatris spicata) disappear into a small sea of yarrow in a sunny section of my old garden. And my native merrybell (Uvularia grandiflora) barely held its own against the onslaught of non-native periwinkle in a shady section. It's not that these natives aren't tough; it's just that the particular non-natives I placed beside them are tougher.
Likewise, there are many natives, such as false sunflower (Heliopsis helianthoides), wild strawberry (Fragaria virginiana) and virgin's bower clematis (Clematis virginiana), that will muscle out any cultivated variety in their path, and should never be planted beside a prized but weak or fussy ornamental.
If gardens are like conversations, the dialogue between gardener and garden in a combination planting is all about what it means to make a cultivated space in the wild and a wild place in the cultivated. It's a contradiction, but the most engrossing tales often are.