Sunflowers for Sunny Places
by Don Janssen, Extension Educator
Gardeners who not so long ago had only a few varieties of sunflowers to choose from now have dozens, from dwarf types only 1 to 2 feet tall to the mammoth types that reach 8 to 12 feet tall and have seed heads up to 20 inches across.
Recent developments include varieties with a single stem that produce multiple branches, "pollenless" types for cut flowers, and numerous new varieties in a wide range of colors from white and palest yellow through bright yellow and orange to bronze, rust and dark red. Varieties with bicolored petals are also available.
Unlike so many other garden flowers, the sunflower is native to North America. And its cultivation by indigenous people goes back at least 3,000 years. Sunflowers were introduced to Europe in the 16th century by Spanish explorers returning from the New World. They were grown more for their ornamental value than for seeds or oil until they reached Russia, where they became an important source of oil. Sunflowers are generally easy to grow. They're not choosy about soil type and will grow almost anywhere except in standing water. Good fertile soil results in the largest flower heads and the meatiest seeds, however. Sunflowers are generally very drought resistant and they rarely require pest control. They do require full sun, however, as their name suggests.
For best results, plant in a well prepared soil tilled to a depth of 8 inches and enriched with compost, manure or other organic matter and/or a general purpose fertilizer. Sow seeds ¼ to ½ inch deep and about 6 inches apart. When the first true leaves appear, thin plants according to the directions on the seed packet for spacing (usually 2 to 2 ½ feet apart in rows 3 to 4 feet apart). Sunflower seedlings are somewhat frost resistant, but they won't survive a hard freeze. Seeds germinate best when the soil has warmed to 70 degrees and plants grow quickly, so it makes sense to wait to plant until warm weather has arrived in late spring.
Sunflowers thrive in hot summer temperatures and tolerate drought, but they do better with an occasional deep soaking, especially when flower heads are developing and expanding. Because they grow vigorously, they benefit from a booster application of fertilizer when flower heads begin to appear.
Tall, single-headed plants may need staking as the seed head becomes heavier.
Sunflower seeds may be roasted for snacks and used in baking as well as used for wild bird feed.
University of Nebraska-Lincoln Extension in Lancaster County is your on-line yard and garden educational resource. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office