Winters in Missouri average as low as -20 degrees Fahrenheit, so wise gardeners choose tough perennials. Plants must be hardy in U.S. Department of Agriculture hardiness zone 5 to survive Missouri's harsh winters.
Native bluebells (Mertensia virginica) greet spring with arching sprays of bright blue flowers. Spreading, evergreen mats of candytuft (Iberis sempervirens) are covered with white flowers in early spring. Fragrant, rounded flowers in every color except blue stand out in spring gardens that include peonies (Paeonia).
Prolific and dependable, black-eyed Susans (Rudbeckia fulgida) bloom all summer if deadheaded. Purple coneflowers (Echinacea purpurea) have tall, spiky, purple or white flowers that butterflies love. Russian sage (Perovskia atriplicifolia) is an airy, silver and blue plant that's drought tolerant.
Fall and Winter
New England asters (Aster novae-anglia) are a trouble-free alternative to mums and come in almost every color. The maiden grass (Miscanthus sinensis) cultivars Bitsy Ben, Gracillimus and Adagio tolerate Missouri's cold winters well. Stonecrop flowers (Sedum spp.) persist well into winter. And hellebores (Helleborus spp.) bring color to January's dark days.