Nothing can brighten a garden as fast as sunflowers. Few flowers are as showy or as tall. They thrive in heat and humidity and are pretty drought-tolerant. The more sunlight, the happier they are.
Sunflower seeds yield a variety of products, ranging from snack food to soap and oil to birdseed. Seeds are a rich source of calcium and other minerals. Stems and heads may be made into paper or used for fuel, and they are also a popular cut flower.
Sunflowers range in height from 2 to 12 feet or more, depending on variety. Mammoth sunflowers are usually grown for their seed, as their flower size is too large for typical flower bouquets. Shorter varieties lend themselves to container gardens. There are single flowers per stem and multiflowering varieties. Single-stem plants produce one large flower per plant, followed by lesser blossoms, and their blooms typically open in a relatively short period. Multiflowering types have multiple flowering branches, producing bunches of flowers over a longer period. These plants blend nicely in a flower bed.
If you think all sunflowers are yellow, think again. There are reds, oranges and cream colors, as well as multiple shades of yellow. There are single colors and bi-colors, single petals and double. And flower heads range from 3 to 12 inches or more.
There are several species of perennial sunflowers. Many grow to be relatively large plants, between 3 to 5 feet in height. Depending on variety, they can also spread. Most perennial sunflowers bloom mid-summer to fall.
Sunflowers adapt to a wide range of soils, but prefer well-drained soil in a sunny location. As their name implies, they like sun; a minimum of six to eight hours is needed for good flower production. Remember, sunflowers follow the sun, so place plants where you can enjoy their faces, and not the backs of their heads.
They like warm weather, so wait to plant when the soil temperature has warmed after all chances of frost. To increase the length of harvest, stagger planting dates a couple of weeks apart. This can give a continuous harvest until frost. Warm temperatures yield faster flower development, and more compact plants bloom much earlier.
Germinating sunflower seeds are sensitive to fertilizer, so allow them to get growing first. After the second set of leaves has formed, side dress with a complete fertilizer, and repeat in four to six weeks. That should be all the fertilizer needed.
Sunflowers are drought-tolerant but will perform better with adequate moisture. Avoid overwatering, which can result in misshapen heads. Insufficient water can reduce the size and quality of sunflowers, but too much water can also reduce growth and lead to root rot. Mulching can help to reduce watering demands and keep weeds at bay.
Sunflowers can be harvested as flowers open. Cut flowers should last seven to 10 days. If you are growing them for seed, allow heads to mature before harvesting. At maturity, the backs of heads are brown and dry. Most yellow petals will have dried up and fallen away. Seeds should look plump, and seed coats will be either solid black or black-and-white striped. To prevent birds from feasting before you cut, wrap heads in cheesecloth or netting. Be sure to harvest before seeds begin to loosen and shatter. Cut the main stalk about 1 foot below the head. Rub seeds loose by hand, then dry and store for later use.
Seeds may be used immediately for birdseed or may be eaten fresh, de-hulled or roasted and salted in the shell.
With cultivar names including “Sunrise,” a bright yellow, to “Sunset,” a deep mahogany, there are new cultivars each year. Check out seed catalogs and experiment. Whatever the variety, sunflowers are quick-growing, undemanding and pretty plants.