We’re going to tell you all about sunflowers so you can be a sunflower expert.
Sunflowers (Helianthus annuus)
It is thought that sunflowers may have been domesticated before corn, as early as 3000 BC in the area that is now Mexico, New Mexico, and Arizona and in the Mississippi Valley by 2300 BC. The plant is certainly native to northern Central America and grew tall and bushy, with many flowers per plant. Evidence suggests that the seeds were used to grind into flour for bread or made into a meal that was mixed with squash, corn, or beans. Various tribes used the plants to create dyes, for oil that was applied to the skin and hair, and the stalks were even used as a building material. Sunflowers were also used as beanpoles, like corn was in the Three Sisters method of growing.
The original sunflower was tall, but had small flowers with relatively small seeds – these were ground as a grain crop.
Spanish explorers returned to Europe with seeds some time in the late 16th century, and the sunflower’s cultivation as a decorative annual spread. English authorities issued a patent for extracting oil from the seeds in 1716, and by the late 18th century, sunflowers were being grown almost exclusively for this purpose. Peter the Great was a proponent of sunflower oil, and encouraged its spread east into Russia. Commercial processing of sunflower oil emerged around 1830.
The Russian Orthodox Church forbids the consumption of a number of oils during Lent, but sunflower oil never made the list. As a result, Russian farmers were growing over 2 million acres of the plant by the mid-19th century. Russian breeders began to break sunflowers into two categories: One type for higher oil content, and another type that produced larger seeds for human consumption. V.S. Pustovoit is credited with developing a significantly high-oil variety. By the end of the century, seeds had made their way back to North America in the hands of Russian and East European immigrants. Seed companies began to advertise Mammoth Russian sunflowers around 1880. Commercial processing of sunflower oil in North America began in the mid-1920s. The cake left over after pressing the seeds for oil became a useful feed for livestock.
In 1930, the Canadian government launched its own breeding program, and a small crushing plant was unveiled in 1946. The demand for sunflower oil spread into the northern US states. In 1964, the government of Canada began licensing a Russian cultivar called Peredovik for its extremely high oil content, and the first hybrids began to appear in the 1970s. By then, there were over 5 million acres of sunflowers being grown in the US alone, and much of this was being exported back to Europe, as it was much cheaper to produce than olive oil, and healthier than animal lard.
Today, of course, there are scores of varieties to choose from, including the really huge types, smaller, compact varieties, pollen-less types for the floral market, and heirlooms that date back to cultivation in Italy, China, and elsewhere. A wide range of colours, sizes, and seed types are now available. A number of varieties have also been bred to produce substantially more oil than Peredovik.
Sunflowers are members of the family Asteraceae, which all form a composite head (capitulum) made of masses of simple flowers (florets) that each produce a seed if successfully pollinated. Sunflowers typically have between 1,000 to 1,400 florets, and potential seeds, per head. The capitulum is surrounded by petals, making the whole structure seem like one single flower. This family is vast, and includes daisies, chicories, dandelions, and, strangely, lettuce.
All sunflowers are highly attractive to bees and other pollinators.
Sunflowers earned their name due to a curious process called heliotropism. During the budding stage of growth, the heads of nearly all sunflowers face east at dawn, and follow the sun throughout the day, facing west at dusk. A flexible piece of the stem (the pulvinis), just below the flower bud enables this curious movement. One other remarkable ability of the sunflower is its use in extracting toxic ingredients from soil. Not only can the plants draw up lead and arsenic, but they were used after the nuclear disaster at Chernobyl to draw up the radioactive chemicals cesium, uranium, and strontium. This is a long-term process known as phytoextraction, but is thought to be less environmentally disruptive than other methods.
Near the end of July, the town of Altona, Manitoba, celebrates the Manitoba Sunflower Festival, an event that has been running for nearly 50 years. Events include live music, Mennonite food and crafts, a quilt show, motorcycle stunts, a dog show, petting zoo, baseball, farm markets, and the crowning of Manitoba’s Sunflower Queen.
Russian Mammoth is a good choice for eating – or sharing with the birds.
How to Grow Sunflowers
Difficulty: Easy. For container growing, choose small varieties. The larger sunflowers have deep roots to anchor them in place and need to go directly in the garden bed.
Timing: Sunflower seeds need warmth to germinate so direct seed from mid-April to mid-May. Seeds can be direct sown as late as June, but will produce flowers much later in the season. Transplanted sunflowers will need staking, as their roots will be restricted by pots.
Sowing: Sow 1cm (½”) deep, and sow about twice as many seeds as you need. Thin this to 30cm (12”) apart for small to medium sized plants, and 60cm (24”) for the tall varieties.
Soil: Choose a site in full sun, with average fertility and good drainage. Sunflowers are not very sensitive to soil pH, and can be grown anywhere in the range from 5.7 to just over 8.0.
Growing: Use an all purpose organic fertilizer about half way through the summer. To aid proper development of seeds you’ll be eating for feeding to birds, dissolve 5ml (1 tsp) Borax in 350ml (1½ cups) of water and spread over 5m (15’) of row. This supplies plants with boron, which is essential for producing big, vigorous seeds. Do not over-apply this solution, though, as too much boron can harm the plants.
Harvest: At the end of summer and into autumn, depending on when the seeds were planted, the sunflower seeds should be ready to harvest. Allow seed heads to dry on their stems. If necessary put a brown bag over the flowerhead and secure it at the bottom to keep squirrels and birds away. The important thing is that as the plant dies back it has time to develop the seeds within their hulls. Afterwards cut off the heads, bring indoors, and (after completely drying out) the seeds can be removed by rubbing and pushing against them.
Storage: To prepare seeds for eating, use the grey or white-seeded variety. Once done, rub the seeds off the big flower head and soak overnight in 4L of water with 250ml (1 cup) of salt. Drain, then dry in an oven at 250 F for 4-5 hours then store in an airtight container. The black seeded types are mainly used for pressing oil or birdseed.
Seed info: In optimum conditions, at least 75% of sunflower seeds should germinate. Stored correctly (cool, dry, and dark), these seeds should last for up to 7 years.
Growing for seed: Sunflower florets open over a period of 5 to 10 days, and are pollinated by insects. To maintain purity of the seed, individual varieties should be isolated by 2-5km (1-3 miles), depending on the size of the crop and its proximity to other growers.
Pests & Disease: Few insect pests cause problems, but watch for damage to the lower stems from squirrels and other rodents. If damage occurs, spray the stems of all your sunflowers with a solution of water, cayenne pepper, and a couple of drops of dish soap.