Although sunflowers (Helianthus annuus) have a corporate side—as a cash crop for their edible seed and oil, and as the highlights of pricey floral arrangements—their nearly universal appeal to gardeners may rest solely on the fact that just looking at them can make you happy.
They're so easy to grow, squirrels and birds can sow a healthy crop by accident underneath a bird feeder. Varieties thrive largely as annuals in all USDA Plant Hardiness Zones, from Alaska to Hawaii. After all, this plant, made iconic by Dutch painter Vincent van Gogh, was first cultivated in the American Southwest around 1000 B.C. and developed for commercial use in the mid-1800s in Russia, where brutal winters stymied grand armies. Today, Russia, Ukraine, and below-the-equator Argentina are among the largest growers of sunflowers in the world.
Yet unless the goal is growing a cash crop, or setting Guinness World Records for tallest sunflower or biggest sunflower head, sunflowers require minimal care. That's a miracle, since sunflowers are a native American plant, "so the largest number of pests co-evolved with them," notes Jim Shroyer, Ph.D., extension crop specialist at Kansas State University. These pests' long and close association with the plant is reflected in their names: sunflower moth, sunflower midge, sunflower headclipping weevil, and sunflower maggot. Many of them are a big problem in Kansas, the Sunflower State, where the Helianthus is the state flower and about 2 percent of agricultural acreage is dedicated to sunflowers. (Then again, wild sunflowers are so plentiful in Kansas "they're considered a weed," says Shroyer.)
But in the home garden? "Mostly, all you see is a little rust," says Venelin Dimitrov, product manager of flowers at Burpee, in Warminster, Pennsylvania.