Garden Sunflower Plants

Requirements

• Sunflowers need a location with full sun and a rich, deep, moist soil that is well-drained. Work a generous amount of compost, rotted manure or other organic material into the soil before planting to improve fertility and moisture retention. Sunflowers need an inch or more of water each week, either from rainfall or irrigation. Grow annual sunflowers from seeds planted directly in the garden. Propagate perennial varieties from cuttings taken in early summer or by division in early spring. Perennial varieties are hardy in U.S. Department of Agriculture zones 5 through 9.

Annual Sunflowers

• The dozens of annual sunflower types include plants ranging in size from 2-foot dwarfs to towering giants that grow up to 15 feet tall. The common sunflower (Helianthus annuus) produces yellow-petaled flower heads with dark brown centers. The flowers sit atop tall, straight stems that vary in height. The Inca Jewels sunflower has a multi-branching habit and produces bright orange petals with yellow tips. Italian White is a multi-branched cultivar with cream-colored petals. Sunbeam's 5-inch pollenless flowers are well-suited to cut flower arrangements. Teddy bear's single and double yellow flowers bloom on plants that grow only 2 feet tall.

Perennial Sunflowers

• Maximilian sunflower (H. maximilliani) is a Midwest native with 3-inch yellow flowers that bloom late in the season, often into October. The plants grow up to 10 feet tall and tolerate dry soils. Thin-leaved sunflower (H. decapetalus) has 3-inch blossoms on 4- to 5-foot plants. The flowers are more proportional to other garden plants, making them a good choice for mixed plantings. H. multiflorus grows 5 to 6 feet tall and produces 5-inch yellow flowers. Several cultivars of this species have double flowers.

Harvesting Sunflower Seeds

• Sunflower heads are ready for harvest when the back of the head turns yellow and the seeds take on a rich brown color. Cut the heads and hang them upside down in a dry, shady location until the seeds are completely dry. When the seeds are dry, they come loose easily when you rub your hand across them. If birds are eating too much of your crop, cover the flower heads with cheesecloth or a paper bag.