Dutch artist, Vincent van Gogh’s painted sunflowers may mark the signature of European Impressionism in the 19thcentury, but the cheerful yellow flowers are native to North America. Sunflowers, like corn, Concord grapes, blueberries and cranberries, originated on this continent and were ferried across the Atlantic hundreds of years ago.
There they made a splash, with dramatically large seed heads and vibrant yellow petals. Most strikingly, the flowers follow the sun in a response called heliotropism. This magical property drew the attention of ancient Aztecs in Mexico, where the flower appeared to mimic a sun worshipper and was deservedly considered an omen of faith.
In contemporary gardens, the common sunflower has made way for new decorative varieties—some dwarf, other multi-branching, mid-sized, with red, orange or ivory petals. But whatever color or size, sunflower cultivation is the same everywhere. Most are easy to grow and will find their way into the annual, perennial or herb garden.
Drought-resistant sunflowers yield a particularly good crop on the eastern Colorado plains, where many farmers have seen a drop in the water table with less irrigation available.
Ron Meyer, Colorado State Extension Agronomist for the Golden Plains, covers three counties but is based in Burlington, Colorado, where Kit Carson County leads the state in sunflower production. “Sunflowers are native to the high plains, a dry-land crop with roots that extend six feet into the soil,” Ron says. The strategy for farmers is to pre-water their soil, allow the seeds to emerge and then water only once again. The rest of the farm water is saved for corn or wheat.
“Sunflowers are a low-maintenance crop. The ground doesn’t even have to be tilled. The farmer can plant in the wheat stubble. It doesn’t require much fertilizer and there’s no problem with pollination. So bees are not as important to it as with other crops. And it’s a beautiful crop, we actually have people stop on I-70 and take pictures,” Ron says.
A new form of sunflower oil called Nusun is soon to be an important food product. “It’s a healthy oil,” Ron says, “second to olive oil in healthy characteristics. It’s so new you can’t find it in the supermarkets yet, but you will. It’s as important a crop as any now.”
Along with wheat and millet, sunflowers are a typical rotation crop for wheat and corn. On the world market, they add to the bird seed, snack food and sunflower oil production each year. The number of acres under cultivation changes annually according to demand, which in Weld County may vary as widely as 4,000 to 2,000 acres. Colorado places fourth in sunflower production with about 200,000 acres under cultivation, behind North Dakota, Kansas and South Dakota.
Begin With A Soil Sample
Although sunflowers are grown as a food crop, they don’t appreciate the high nitrogen levels often found in vegetable gardens. Plant them in a sunny location among annuals, perennials or herbs.
First, says Jerry Alldredge, Colorado State University soils and crop agent for Weld County, get a soil test. Too often home gardeners fertilize their soils excessively. Sunflowers actually prefer a lean soil with good drainage. A clay loam is perfect, which mimics their origins. Sunflowers are true prairie flowers widely adaptable.
Jerry offers a predictable form of germination. Spray the seeds with water and place them in a dampened, but not wet, paper towel. Put the towel in a plastic bag and wait a day or two for germination. The seeds that germinate first will be the strongest. Should you have a fistful of leftover or questionable sunflower seeds, you’ll know which should be planted in your garden. Sown directly on the ground, the seeds will take five to ten days to germinate.
Sunflowers need space, about 12 inches apart, even for the dwarf varieties. Very large sunflowers should be sprinkled throughout the garden. Plant the germinated seeds one to two inches deep in the garden, but no deeper than three inches. Most like regular watering about 20 days before they bloom, but won’t need a lot of water otherwise. They should receive at least six hours of full sun a day.
How To Avoid Pests
All sunflowers are annuals, propagating by seed only. Jerry says that trial plantings in Nebraska suggest that many pest cycles can be broken if seeds are planted June 5. The bugs simply have moved on. But you may not have any pest problems in Colorado.
Although the Midwestern prairie is home to most of the 50 species of native North American sunflowers, most grown in Colorado are remarkably pest free in our arid climate. Only a few insects, like the headmoth, will attack them.
Various diseases like rust can be avoided by choosing rust resistant strains. The seed package will tell if the strain you’ve chosen is resistant. Jerry suggests the best way to avoid diseases is to rotate plants each year, both vegetable and annual flowers, so that diseases don’t become entrenched in the soil.
On the farms, sunflower seeds with over 40 percent oil are set aside for oil production. Seeds with a lower percentage of oil are saved for snacks and birdseed. That makes a sunflower patch an excellent wildlife habitat for birds and squirrels. But if you’d like to harvest the seed heads, cover the flower with cheesecloth or a sheer plastic netting as the seeds are forming. Cut the flower with about a foot of stalk in September or October and store it in a dry, dark room. You can place a paper bag over the seed head to catch the seeds as they fall.
Sunflower oil is best used for salad dressings where the oil is not heated. For this recipe we’ve used canola oil, which can take a high heat. The exception is Nusun sunflower oil, soon to be available, which can be used for roasting and frying.
- 4 cups old-fashioned uncooked oatmeal
- 1 cup chopped walnuts or pecans
- 1 cup hulled sunflower seeds, unsalted
- ½ cup canola oil
- ½ cup honey
Combine all ingredients and roast at 350 degrees until you reach the desired golden color. Stir every 10 minutes. It will take about 20 minutes.
- Add: ½ cup chopped dried figs
- ½ cup raisins or currants
- ½ cup dried cranberries
- Store in the refrigerator.
Roasted Sunflower Seeds
In two quarts of water, add 1/2 cup salt. Soak unshelled sunflower seeds overnight, drain and allow to dry completely. Then bake the dry seeds for 30 minutes in a 350-degree oven.