Summer annual flowers provide brilliant colors for your garden. These flowers last throughout the hot, dry summer weather when the heat-sensitive spring flowers have faded. Group the flowers together by height to achieve the best design. Plant the taller flowers behind the shorter ones. Annuals provide you with the opportunity of trying different types of flowers each year since they are not a long-term addition to your garden.
California poppy (Eschscholzia californica) is a silky, cup-shaped flower that is about 3 inches across. The flower stem reaches 12 to 18 inches tall and the feathery green leaves spread out in 6- to 12-inch-wide clumps. Brilliant hues of orange, yellow, pink, white and red fill wildflower gardens when California poppies are added.
Common stock (Matthiola incana) grows flower spikes 12 to 24 inches tall. One-inch blossoms with four petals cluster on top of these spikes. Common stock produce blooms in white, pink, red, yellow and purple shades. Lance-shaped, gray-green leaves grow in bushes 12 inches wide. Use common stock annuals near outdoor sitting areas so you can enjoy the sweet fragrance of these flowers.
Cornflower (Centaurea cyanus) is a bushy plant of narrow, lance-shaped leaves with a touch of silver color. These clumps of foliage are 12 inches wide. Stems topped with fluffy flower heads reach 12 to 30 inches tall. These 1- to 2-inch flowers grow in shades of white, blue, purple, pink or red throughout the summer. Cornflowers make excellent, long-lived cut flowers and are a durable addition to any wildflower garden.
Hollyhock (Alcea rosea) grows 3 to 6 feet tall and spread in 2-foot-wide clumps of round, green leaves. The hollyhock shoots up thick flower stalks with large spires of 5-inch, bowl-shaped blossoms. White, red, pink and yellow shades fill the garden midsummer through fall. To achieve flowers in the summer, buy seedlings from your garden center or start your own seedlings indoors 8 weeks before the expected date of the last spring frost.
Snapdragon (Antirrhinum majus) produce narrow, bright green mounds 8 to 18 inches wide. Slender flower stems tower 1 to 4 feet tall the foliage and produce spikes of tubular blossoms. Snapdragons appear in nearly every color except true blue all summer long. Use these velvety blooms as cut flowers or in cottage garden designs.