1996 has been proclaimed ‘The Year of the Sunflower’ by the National Garden Bureau, an organization that promotes gardening throughout the United States. The sunflower is enjoying renewed popularity as an ornamental these days, but sunflower remnants found in its native North America have been estimated to be in existence as early as 3000 B.C.
The sunflower has long been used as a source of food. Native American populations ground the seed into a flour to bake into breads and mix with vegetables. Spanish explorers are thought to have returned to Europe with the sunflower, to be used primarily as an ornamental. The Russians are credited with adapting the sunflower as an oil crop.
The sunflower is in the Compositae family, a large, diverse family that also includes dandelions, asters, lettuce, marigolds, chrysanthemums, thistles and yarrow. The flower structure of the sunflower will surprise you upon closer inspection. What most people typically think of as one flower is actually a cluster of many flowers that botanists call a “head.” The outer, more showy flowers that appear to be petals are called ray flowers. The smaller, tube-shaped flowers in the center of the head are called disk flowers. The ray flowers are usually sterile, so they do not produce seed, but they are brightly colored to attract insects and the pollen they carry from other sunflowers. The disk flowers are the ones that actually receive the pollen and subsequently produce the seeds.
Gardeners will find two different types of sunflowers available from garden centers and mail-order catalogs – those that are grown for their edible seeds and those that are grown primarily as ornamentals. Traditional varieties were generally quite tall (5 feet plus) with bright yellow blooms. Modern cultivars now offer a range of orange, gold, lemon yellow, bronze, amber, mahogany red, and even white. Another new development is a more highly branched plant that may carry numerous smaller flower heads rather than one large head. Some cultivars have been bred to fill the center with additional rows of ray-type flowers, giving a fuller, “double-flowered” appearance. Today’s catalog offers sunflowers ranging in height from dwarf types (1-2 feet) to intermediate (3-4 feet) to tall (5 feet and up).
Sunflowers have been gaining prominence as a cut-flower crop in the florist industry, and breeders have responded by creating new hybrids that bloom without producing pollen. These new floral cultivars solve the problem of pollen stains on fabrics and also extend the vase life of the cut flower.
Sunflowers are easy to grow in just about any type of garden soil and climate, but choose a sunny location for best flowering. Although the sunflower is generally considered to be a warm-season crop, most will tolerate a light frost.
To harvest sunflower seeds for eating or for feeding birds, cut the head when at least two-thirds of the seeds are mature. (The outer shell of the seed will be hardened, and the back of the head will be brown and dry.) You may need to protect your harvest from the birds by covering the maturing head with cheesecloth, netting or a paper bag. Cut the head from the plant, leaving 1-2 feet of stem attached. Hang the heads in a paper or cloth bag to catch the falling seeds, and place them in a warm, well-ventilated area for a few weeks to cure.