Annual flowers help to fill in beds with their bright colors and unusual foliage. An annual is defined as a flower that grows, blooms and dies all in one season. Many annuals, like pansies, are hardy and grown in cool seasons to provide splashes of color. Tender annuals, such as impatiens, cannot withstand freezing temperatures and so are planted in spring when the threat has passed. Remember that most annual flowers require four to six hours of sunlight per day.
Pansy (Viola x wittrockiana) is a low-growing, annual flower that has a long flowering season. Growing 8 to 12 inches tall and 6 inches wide, the pansy comes in a rainbow of colors, including yellow, purple, white, coral and crimson. According to Fine Gardening magazine, "the flowers have a spurred lower petal, 2 upper petals, and 2 lateral petals." Pansies are ideal tucked into containers or along garden borders for their low height and brilliant colors. As a hardy annual, they thrive in cool soil temperatures. Pansies require full sun to part shade and well-drained soil that is nutrient-rich. To promote a long flowering season, deadhead the spent pansy blooms as soon as they are noticeable. Hardy in all USDA zones.
Marigolds (Calendula officinalis) are a common annual flower with a clumping habit and rapid growth rate. Growing 1 to 3 feet tall and wide, marigolds have clustered flowerheads in shades of yellow and orange. Summer-blooming, they are ideal planted in flowerbeds and containers for their bright colors. Marigolds also happen to be edible annuals to use during a dinner party for an unexpected touch. A butterfly attractant, marigolds have alternate leaves that grow along the branching stems. To extend the blooming season, remove the old marigold blooms. Marigolds require full sun to part shade and well-drained soil. Hardy in all USDA zones.
Impatiens (Impatiens wallerana) is a late spring to fall blooming annual flower, making for a long-lasting annual variety. Growing 8 to 24 inches tall and 10 to 12 inches wide, impatiens grow in a wide range of colors including, orange, red, pink, white and purple. The stems of impatiens are succulent and the foliage is fleshy and bright green. A popular bedding plant, impatiens are ideal tucked into a shaded area of the garden where color is needed. The flowerheads of impatiens are five-petaled to contrast with the deep green foliage. Impatiens require part to full shade and well-drained, humus-rich soil to thrive. Hardy in all USDA zones.