Few gardening techniques are as time- and cost-effective as filling your garden with flowers that bloom all summer. A large selection of annuals---plants that flower, set seed and die in a single growing season---blooms from early summer to frost. These hard-working annuals keep gardens vibrant while permanent garden ornamentals bloom and fade. They come in all forms, colors and sizes, from rapidly spreading ground covers to showy, shrub-sized plants.
Indian blanket (Gaillardia pulchella), an aster family annual, is native to the eastern and southern United States. Plants have attractive, oblong greenish-green leaves up to 3 inches long. Standing 1 foot to 18 inches high and up to 1 foot wide, Indian blanket flowers with daisy-like blooms from June until frost. Blooms on wild plants have yellow, red, or bi-colored rays (petals) around reddish-brown centers. Commercial cultivars of Indian blanket are available in additional colors, including maroon and orange, according to the Missouri Botanical Garden.
Use this largely pest- and disease-resistant annual in rock gardens, containers, or massed in flower borders. It is happiest where summers are hot and dry. Plant it in well-drained, sandy soil and full sun after all danger of frost has passed. Deadheading---pinching off spent flowers---will keep the plants neat and may produce longer bloom.
Garden balsam (Impatiens balsamina), native to India and Asia, stands from 6 to 30 inches high and 6 to 18 inches wide. Its thinly branched, upright stems have lance-like, toothed pale green leaves. From May until frost, the plants produce cup-like, 2-inch spurred flowers. Camellia-form cultivars producing dense, double flowers are the most popular of these annuals. Flower colors range from solid white and shades of pink, purple and red to bi-colored.
Garden balsam is a good choice for edgings, containers and shady borders, advises the Missouri Botanical Garden. It appreciates partial shade where summers are hot. Plant it after the last spring frosts infertile, moist, well-drained soil. Pinching balsam back when it reaches 4 inches high results in bushier plants.
Native to Central America, globe amaranth (Gomphrena globosa) is another upright, branching annual. Standing from 1 to 2 feet high, it has narrow, elliptical green leaves. From June until frost, globe amaranth's brilliant magenta flower bracts, however, upstage its tiny, bright yellow, true flowers. The globe-shaped, papery bracts resemble clover blooms, according to the Missouri Botanical Garden.
Cultivars of this plant offer a host of bloom colors, including white, pink, red and several shades of purple. Use this annual in flower borders, containers, or rock gardens. Plant it after the last spring frost in full sun and averagely moist, well-drained soil. While drought-tolerant, it's susceptible to mildew in prolonged dry periods. Tall plants may benefit from staking.