Sunflowers (Helianthus spp.) are the optimists of the flower garden, turning their bright faces to follow the sun as it travels the summer sky each day. These golden-bloomed plants come in annual and perennial varieties, and are raised for consumption, cattle forage and oil production as well as the ornamental value of their blooms. The cultivars range from tiny to towering, but all share the same general flowering season: The flowers bloom from midsummer through fall.
Wild Sunflower Is Old
Native Americans cultivated sunflower about the same time they cultivated corn (Zea mays), and archeologists place the wild sunflower (Helianthus annuus) in current-day Arizona and New Mexico at roughly 3000 B.C. The original sunflowers were annuals only 1 yard high brightening the fields from midsummer through fall.
Native Americans used the seeds of the sunflower to make flour but also ate them right out of the shells for snacks. They also squeezed oil from the seeds and used the plant parts to make purple dye and the dried stems as building material.
The original wild sunflower is the state flower of Kansas. You can still grow wild sunflowers from seeds available in commerce. The flowers are only 3 inches wide, but the blooms are prolific.
Annuals Are Simple
The toughest job about planting annual sunflowers is selecting one or two cultivars. For maximum "wow," pick the giants, but remember that some types grow 25 feet tall and flowers can reach 32 inches across. Sow the seeds in sunny soil in spring, after all chance of frost has passed, and expect blossoms two to three months after the seeds germinate. The flowers can last months before wilting.
Sunflower plants are tough cookies, simple to grow and hard to kill. They thrive in almost any soil and, once in place, prove drought-tolerant. For the biggest, brightest blooms, irrigate their soil regularly during the growing season. Staking the stalks may be necessary if your cultivar grows over 3 feet tall.
For the bigger-is-better crowd, try "Grey Stripe" sunflowers (Helianthus annuus "Mammoth Grey Stripe"). Its stalks rise like Jack's beanstalk to 8 to 12 feet tall, with flowers up to 12 inches across. If you want a shorter variety, then opt for "Teddy Bear" (Helianthus annuus "Teddy Bear") for its cushionlike flowers that last five weeks on a 2- to 3-foot-tall stalk.
The joy of perennial sunflowers is that you plant once for many years of flowers. Perennial sunflowers grow in bush form, with each bush producing many blossoms; the plants typically are hardy in U.S. Department of Agriculture plant hardiness zones 4 through 9. Perennial sunflowers may start blooming a little later in summer than annuals and hold their flowers through October. Look for cultivars that grow well in your garden's soil and sun conditions.
Gardeners in Europe have long loved the sunflower cultivar "Lemon Queen" (Helianthus "Lemon Queen”), a perennial bush that grows upright to 7 feet tall. It offers soft-yellow, daisylike flowers from late summer through fall.
Be a little careful with perennial sunflowers. They are so tough that they can escape cultivation and shoulder out native plants.