Sunflowers seem to have the ability to lift the spirits, creating a feeling of inner happiness. If you’d like to welcome this vivacious summer flower into your garden this year, then this home gardener’s guide on how to grow sunflowers can show you how.
In this home gardeners guide on growing sunflowers you will learn:
- The meaning of sunflowers
- Sunflower origins and history
- Best ways to grow sunflowers
- Sunflower pests and diseases
- How to harvest and store your sunflower seeds
Sunflowers have long been a children’s favorite, the sheer size that some varieties can grow to make them fun and exciting. They are perfect for a little bit of friendly competition to see who can grow the tallest flower. They are also great for creating a striking floral arrangement or to add height to the back of a flower border, where they are best grown in groups. Other than their beauty, sunflowers also provide nutritious seeds that you can eat or feed to birds and other animals.
The large yellow flower heads of sunflowers with their
bright yellow petals, which so much resemble the sun, are fittingly called
“rays.” There are lots of varieties to choose from, varying in size
from small to giant, and all are fairly easy to grow even for a novice gardener.
Why Sunflowers Follow the Sun, their Meaning and History
Not only are sunflowers very beautiful, but they are also fascinating. There is some confusion about whether or not sunflowers follow the sun and the reason for this may be because they only display their sun following behavior for part of their life and not when they are blooming.
Why Sunflowers Follow the Sun
Young sunflower heads follow the sun across the sky. This phenomenon is known as “heliotropism.”
Sunflowers contain auxins, which are growth hormones sensitive to sunlight. Auxins don’t like sunlight and naturally migrate to the shadiest parts of the plant. As the sun moves, the auxins are continually driven around the stem causing it to grow a little in each area that they settle. This causes the head of the sunflower to move, making it appear to follow the sun.
As the flower heads develop and bloom, they become fixed facing east, but the heliotropism still makes the flower heads rise up to face the sun as it rises, which also helps to maximize photosynthesis. Facing east helps the flower to warm up quickly and attract more pollinating insects.
When the sunflower matures, and seeds start to develop, the plants no longer display heliotropism and finally droop down due to the weight of the seed.
Sunflowers are a flower of happiness. They symbolize loyalty, devotion, honor, integrity, sincerity, and longevity. It is thought much of this meaning comes from the sunflower’s namesake, the sun. The sun shines down energy in the form of heat and light, while sunflowers provide us with energy by lifting our spirits, and from their nourishing seeds and oils.
An ancient Greek myth about Apollo and the woman who loved him named Clytie, tells of Apollo spurning Clytie and turning her into a sunflower. Despite this, she continued to love him which is why sunflowers are symbols of adoration and loyalty in many parts of the world.
In China, sunflowers symbolize long life and good fortune, due to their imposing size and vibrant color they also symbolize vanity.
In the Native American culture, sunflowers mean harvest and bounty, because they provide food in the form of seeds & also color pigments
Today sunflowers are prized for their beauty, seeds, and oils, which can be used for beauty and food products. But these large yellow flowers have been the focus of many a famous artist, probably the most famous being Vincent Van Gogh, but Paul Gauguin and Gustav Klimt have also featured this beautiful plant in their paintings.
The name “Sunflower” or correct Latin name “Helianthus” comes from the Greek words “Helios” which means sun and “Anthos” which means flower.
Sunflowers have been purposefully grown from around 3,000BC, which has been discovered from sunflower seeds being found at archeological sites. In the United States, sunflowers were cultivated by Native Americans in the Mississippi river valley for their seeds, oil, and fiber and also as a medicine.
When Europeans started to settle in the United States, they prized the sunflowers they found there and sent seeds back to Europe. Sunflowers became popular as an ornamental plant in many English cottage gardens as can be seen in the paintings from Van Gogh’s and his counterparts.
Sunflowers also gained great popularity in Russia, because their oil could be eaten without breaking their strict religious dietary laws. Russian growers in the 20th Century started to breed selectively to maximize the plants’ oil content and make it more disease resistant.
By the 1960s specially selected sunflower cultivars were being grown commercially in the United States on an industrial scale, mostly to produce vegetable oil.
Sunflowers remain a popular commercial crop in many parts of
the world, as the oil has many uses, from cooking and cosmetics to biofuel.
How to Grow Sunflowers
Sunflowers are a hardy plant and will grow even in relatively poor soils. They can tolerate a soil pH of between 6.0 and 7.5 quite happily and are drought resistant due to their ancestry growing on the vast American prairies. They do not however like waterlogged soil, so if you are in a heavy clay area you may have to do some soil modification to prevent this problem.
There are a vast number of sunflower varieties for you to choose from. Sunflowers don’t just come in yellow either, there are also other color options available to try too. Here are a few varieties to illustrate this:
- Skyscraper – A very large sunflower with petals of around 14 inches in length. It can grow to 12 feet in height and has a large seed head.
- American Giant – really lives up to its name featuring a large seed head and growing to heights of around 15 feet it can also span up to a foot in width!
- Russian Mammoth – Is an easy to grow specimen with large seed head, which is popular at county fairs because of its height of 12 feet.
Dwarf sunflowers are generally more popular for garden ornamental displays of for flower arrangements. They grow to a maximum height of three feet and look great in bunches.
- Little Becka – This sunflower could also be classed in our next category of colored sunflowers, but it is also a dwarf variety growing to only one or two feet in height. It has deep orange petals with yellow tips and will add a vibrant splash of color to any garden or arrangement.
- Sundance Kid – Was one of the first sunflower varieties to be domesticated. It is unusual as it has multi-layered petals with a small seed head. It stands at about one to two feet in height.
- Sunny Smile – Is a perfect miniature of one of the larger sunflower varieties, with a large seed head for its size it can grow from 12 to 15 inches in height. It has particularly stout stalks and can take abuse from pets and children in the garden.
Hybridizing sunflowers has created some amazing colored varieties, perfect for adding a splash of color to your flower arrangements or garden borders.
- Earthwalker – features a golden halo around its large seed head, which turns to deep reds.
- Terracotta– has colors perfect for fall, ranging from burnt orange, golds and deep yellow.
- Ms. Mars – has beautiful red and purple hues that graduate to subtle yellow at the tips.
The best way to grow sunflowers is by planting the seeds directly into the soil where they are to be grown. The seeds can be sown as soon as any danger of frost has passed in the spring, or you can start them indoors in individual pots. The small peat pots are useful for this purpose as they biodegrade. Ideally, the outdoor soil temperature should be between 55- and 60-degrees Fahrenheit before planting.
To plant the seeds outdoors:
- Make a shallow trench in the soil of about 1 ½ to 2 inches in depth. If you are going to be growing several rows, then the rows should be around 2 to 3 feet apart to allow the plants to gain maximum light as they grow.
- Place a seed approximately every 6 inches if you are growing the larger headed seed varieties. For smaller varieties, used for flower arranging or decorative planting, space them closer together a minimum of 2 inches apart.
- Place the soil back over the seeds and water gently so you don’t wash them away. The soil should be kept lightly damp, not wet, you can test this by digging your finger down alongside the seed trench to make sure the soil is damp and not dry or wet.
- The seedling sprouts should appear between 7 and 10 days after sowing.
- Once the seedlings have acquired their second set of leaves, they should be thinned out to 2 feet for larger headed plants and 1 foot for smaller ones.
- Depending on growing conditions and seed variety, the plants will mature in 80 to 120 days.
- If you wish to prolong your sunflower season, sow a new row of seeds every two to three weeks until the first frosts in the autumn. By doing this you can enjoy beautiful flowers throughout the summer months.
If you want to start your seeds off indoors, fill your peat pots or seed trays with multi-purpose compost and sow an individual seed into each one. Keep moist, not wet. When your seeds have germinated allow the seedlings to grow their second set of leaves then transfer them into larger pots. Keep them in a warm sunny place and when they reach 12 inches you can plant them in the garden or put them into large ornamental pots to place on a patio or deck. Make sure that the pot you select will be big enough to allow the root ball to grow sufficiently, or you will stunt the growth of your sunflowers.
Unless your soil is of particularly poor quality, your sunflowers shouldn’t require fertilizing. If you do want to give them a boost, it is best to add a slow release granular fertilizer to the soil. Over-fertilizing can cause a delay in blooming.
The root ball will spread quite widely, which helps make the plant stable and fairly drought tolerant. Because sunflowers hate having their roots in waterlogged soil, it is best to water deeply every two to three days, giving the soil time to drain in between.
If you have particularly heavy clay soil, you may need to add soil amendments in the form of organic matter. Clay soil is generally nutrient-rich, so fertilizer shouldn’t be necessary. Another option is to create raised beds where you can use compost and grass trimmings to create a light, nutrient-rich soil.
Adding a layer of mulch to about 2 to 3 inches in depth around your sunflowers will help discourage weeds and helps retain moisture lost through evaporation. This can be useful in warmer areas or in sandy soils where the soil becomes dry quickly.
Sunflower do not generally require staking, but if you live in an area that is prone to wind, then it can be advisable as a precaution, particularly if you are growing very tall varieties with large seed heads.
If you are growing sunflowers for their height, there is no need to pinch them out. If however, you are growing them to use in floral arrangements, pinching out will stunt the growth of the plant and cause it to produce a lot more blooms, which can be beneficial. Pinching out is the process of removing the growing tip of the plant when it reaches about 8 to 10 inches in height, you can do it by pinching the tip with your thumb and forefinger.
As your sunflowers start producing seeds, the local wildlife will take full advantage. That is unless you take precautions to prevent this. If you enjoy watching the birds and squirrels feast on the bounty provided by your sunflowers that’s fine, but if you want to use the seeds for yourself you will need to cut the heads off when they droop and allow them to dry before removing the seeds.
Deer can be a big problem as they are rather partial to the tasty young leaves on a sunflower. You can use chicken wire supported by sturdy 6-foot bamboo stakes to deter them.
As the sunflowers heads droop and no longer turn upward to face the sun and the underside of the flower head turns from green to brown, they will be ready to harvest.
Remove the seed head leaving a foot of stem still attached. Hang them somewhere warm and dry and ensure they have plenty of ventilation. Hanging them helps prevent rodents from reaching them. Allow them to dry out for several weeks and when they are completely dry you will be able to easily remove the seeds by rubbing two sunflower heads together, you can also use your fingers or a kitchen fork. Spread the seeds out on a tray and allow them to dry for a few more days before storing them in airtight containers. Glass mason jars are perfect for this purpose. Keep them in a cool dark place to retain the oils and flavor of the seeds.
Be aware that all parts of the sunflower give off growth inhibiting substances that can affect other plants. For this reason, keep them away from pole beans or potatoes.
Pests and Disease
Sunflowers are quite hardy, but they can sometimes become infected by fungal disease including rust and mildew.
Mildew – The oldest leaves are generally the first to become infected. The mildew appears on the underside of the leaves causing them to turn mottled and pale before withering and eventually dying. Warm humid days combined with cool damp nights are the favorite conditions for mildew. It spreads its spores in soil, wind, and rain and can also contaminate garden tools.
Rust – This disease causes yellow or white spots that gradually turn dark brown or black. The spots appear on the tops of the leaves. It can spread to the entire plant and can be contracted from weeds, including shepherd’s purse, wild mustard, lamb’s quarters and pigweed.
To get rid of these diseases keep a careful eye out as catching them early is preferable. Treat by spraying with a garden fungicide and follow the directions given on the label. It is best to burn badly affected plants to stop the disease from spreading to healthy ones. Ensure you disinfect your garden tools, this can be done by dipping them in a mixture of 4 parts water to 1-part household bleach. Ensure you don’t cross contaminate plants with your hands or garden gloves, keep them clean.
Sunflower Moth – This small grey moth will lay its eggs on the developing sunflower blossoms. The caterpillars are a yellow-green color with 5 brown stripes across their backs. They will feed within the flower head and this destroys the seeds. Remove any caterpillars you find and squash them before disposing of them. If the plant has become infected, you can dust it with a product that contains Bacillus thuringiensis (Bt) this is a bacterium that kills the caterpillars. Bt is destroyed by sunlight and rain so it can be necessary to treat the plants several times. Follow the directions given on the label.
Growing sunflowers can be great fun and these beautiful happy blooms give pleasure not only when they are flowering but also afterward with their seeds and oil.
Sunflowers can be grown to give height in a garden border, or to create a colorful focal point. They are good for using in floral displays and with the colored varieties, you can now find even more sunflowers to fit your color scheme.
The main reason for sunflower growing around the world is for their seeds, oils and plant fibers which have great commercial value.
Whatever your reason is for growing sunflowers I hope that you enjoy it and have great success in your endeavors.