The Best Annual Flowers for the Midwest

Full or Filtered Sun

• Flowers in various shapes, colors and sizes grow well in Midwestern gardens with full or partial sunlight. For example, moss rose (Portulaca grandiflora), for USDA zones 5 to 11, features small, double-bloomed flowers in pinks, yellows and oranges, grown as ground cover or in containers and hanging baskets. Hundreds of petunia varieties (Petunias spp.) with large or small colorful blooms thrive in gardens, containers and as ground cover for USDA zones 5 to 9. Zinnias (Zinnia spp.), suitable for USDA zones 2 to 11, grow up to 3 feet high in full sun with showy flowers in orange, white, pink, coral, lavender or yellow. Floss flowers (Ageratum houstonianum), for USDA zones 2 to 11, reach 6 inches to about 2 feet tall with small, soft, feathery blooms in shades of purple, lavender, blue and pink.

Shade

• In the Midwest, annuals and some perennials in full or mostly shaded flower beds can generally tolerate a few hours of early morning sun, depending on the species. Impatiens varieties (Impatiens wallerana) in hundreds of colors thrive in shade and partial sunlight in USDA zones 4 to 10. Impatiens require frequent watering, especially in hot weather and they cannot tolerate temperatures at or below 32 degrees. Purple and lavender wishbone flowers (Torenia fournieri), commonly planted in gardens, beds or window boxes in USDA zones 2 to 11, must be shaded from the hot afternoon sun. Begonias (Semperflorems cultorum group) are perennials for USDA zones 10 and 11, but are grown as summer annuals in cooler Midwestern climates. Begonias prefer filtered shade and may grow 1 foot high. Begonia plants produce red, white and pink flowers. For pink-colored greenery, the polka dot plant (Hypoestes phyllostachya) is noted more for its foliage than flowers. Often used as ground cover, this evergreen is a perennial but is grown as an annual in USDA zones 4 to 7. Plants reach nearly 2 feet high, featuring ovate green leaves spotted in shades of pink, rose and lavender.

Cold-Hardy

• Most summer annuals last until the first frost, however, some flowers better tolerate occasional cold temperatures. “Cold tolerance,” notes University of Minnesota Extension, means plants can live through early spring and fall frosts. Flowering plants that can generally tolerate temperatures to the mid-20s include pot marigolds (Calendula officinalis) and African marigolds (Tagetes erecta). They are suitable for all USDA plant hardiness zones but only for summer outdoor planting in zones 2b to 7a. Sunflowers (Helianthus annuus), with their bright yellow, brown and red petals, require full sun and well-draining soil. Like marigolds, sunflowers grow in all USDA plant hardiness zones but only for summer outdoor planting in the Midwest. Other cold-hardy perennials that are often planted as annuals in USDA zones 2b to 7a include snapdragons (Antirrhinum majus) for USDA zones 7 to 10; black-eyed Susan (Rudbeckia hirta) for USDA zones 3 to 7; phlox (Phlox drummondii) and sweet pea (Lathyrus odoratus), both for USDA zones 2 to 11.

Drought and Heat Resistant

• Midwestern summers can become very dry, especially when Mother Nature provides less than 1 inch of rain per week. If you are not able to water regularly, plant drought-tolerant and heat-resistant flowers, advises the University of Missouri Extension. Melampodium (Melampodium paludosum), has tiny yellow flowers that resemble daisies. Plants prefer full sunlight and hold up well in summertime heat and humidity. Globe amaranth (Gomphrena globosa) features pink, purple or red flowers with green leaves on upward stems that grow 1 to 2 feet tall. Both are for USDA zones 2 to 11. Dahlberg daisies (Dyssodia tennuiloba) are perennials for USDA zones 9 to 11 but plants grow as annuals in the Midwest. In USDA zones 3 to 10, gaillardia (Gaillardia x grandiflora) -- also called blanket flowers -- produce yellow and orange daisy-like-blooms. Gaillardia can tolerate dry soils.