One flower represents hot Summer days and the golden rays of an Autumn sun better than any other: the Sunflower. Sunflowers are part of a large family known as Helianthus (he-li-an’ thus). This is a Greek word literally meaning “sun” and “flower”.
There are at least 60 recognized species and many more cultivars and commercially sold varieties. The Sunflower is one of the world’s best known and beloved flowering plants. It is the State Flower of Kansas, USA and the National Flower of Peru, Russia and the Ukraine. It is also the symbolic flower of the Vegan Society and symbolic flower used by the Spiritualist Church. In the language of flowers the Sunflower represents: Adoration, Fame, Lofty and Pure Thoughts, Loyalty, Pride, Recognition, Riches, Truth and ‘You are Splendid’, which most certainly describes these remarkable natural treasures.
Almost all Sunflowers are natives of the Americas. The annual species appear to have originated in Central America and many of the perennial species are wildflowers commonly found in much of North America. They have been cultivated by the Indigenous Indian Tribes throughout the entire region since at least 2300B.C. or earlier. There they are often referred to as the ‘Four Sister’ grown in combination with the other three essential vegetables: Beans Corn and Squash. The plant was both important for its edible qualities and as a religious icon that most closely represented their relationship and often worship of the Sun.
Because the various species interbreed easily there are hundreds of unusual garden varieties. Most of the original annuals species are large plants some growing to 4m/13.4ft or more! The tallest giant annual Sunflower “officially’ on record was rather recently grown in Germany and towered over 21ft/6.3m. Unofficial records suggest that Sunflowers can attain 40ft/12m or more! Perennials species are often bushy, shrubby or cane-like between 1-5m/3.34-16.7ft.
The Sunflower is actually a conglomerate of between 1000-2000 individual small florets which are arranged in a perfect geometrical spiral pattern in the central floral disc. The outer florets that hold the true petals are sterile. The inner florets in the geometric spiral are fertile and produce both pollen and/or the seed.
The Common Sunflower, H. annus, is an annual species. It is best and biggest when grown from seed where the plants are meant to grow. But can also be started in containers in a very bright, sheltered and warm position, and then the container seedlings are planted out very carefully. Any root damage can set the plant back or cause them to permanently stunt. In cool climates, Sunflowers are often started early in the heated glasshouse or with bottom heat. In mild climates, the best plants are often produced from sowings made once the air and ground temperatures are thoroughly warmed. These warm weather sowings often rocket away at a spectacular pace and produce dramatic results when well-cared-for.
There are easily more than 50 distinct varieties of annual Sunflower; possibly twice that many. These vary from remarkable giant flowered tall varieties like California Grey Stripe, Giant Russian Mammoth, Mammoth, Sunzilla, Skyscraper, Titan and many others which are often grown in competitions for their towering canes; producing usually one giant flower head that can sometimes measure over 1m/3.34ft across! The tallest Sunflowers come from this group. The biggest flower heads usually do not come from the tallest plants, but from those plants that are robust and stocky and grown with plenty of surrounding space in enriched and moist land.
Perhaps the finest of these large and taller varieties are Royal Crown and Yellow Empress. Royal Crown produces impressive large blooms on robust and stocky plants. The flower petals are often much larger and longer than most other Sunflowers and occasionally double. This does create a true crown of long, pointed and sometimes wavy petals which is very beautiful and most dramatic. Royal Crown also produces impressive seed heads with excellent quality kernels quite suitable for eating and beloved by birds, especially Finches. It reseeds easily and usually comes true from seed. Yellow Empress is quite similar but plants are very robust and grow taller; producing one large head up to 25cm/10in across. Flower heads are usually held erect while in bud and flower. Seed heads droop with their weight and are most impressive for cutting, exhibition and for their edible seed.
Other varieties of the Common Sunflower include what are commonly known as ‘Cut-and-Come-Again’ Sunflowers. There are single and double forms of this lovely annual cut flower, once immortalised by Vincent Van Gogh. These are mostly robust and tall plants roughly 2-3m/6.7-10ft. Their ultimate height and stature is largely dependent on their climate and growing environment. These produce one large flower head sometimes with several small side heads all at the top. After these finish the plant often produces many branches that carry several smaller blooms over a long period. These smaller branches and more diminutive-sized blooms are an ideal size for cutting. Some of the finest of these branching Sunflowers include: Ikarus, Sonja, Soraya and Valentine (5ft) amongst many others.
In recent years truly dwarf Sunflowers have been developed. These are ideal for containers, the commercial cut-flower trade and for the border or smaller garden. Plants are identical in proportion to their taller relations but usually only grow 40-100cm/16-40inches more or less dependent upon climate and growing environment.
Some dwarf varieties are branching while most produce one to several blooms at the top of a robust cane. These singled stemmed dwarf forms make ideal cut-flowers so have become most popular additions to the Florist trade. Most are in classic yellow shades but there are bronze, cream, golden, orange and zonal patterns as well as double forms. They make an excellent dwarf annual hedge or container plant.
There are upward of 30 dwarf forms available including Moonlight (pollenless), Munchkin and F1 Premier. Big Smile is a classic dwarf that is famous for flowering from seed in only 50 days! Another advantage to the dwarf forms is that many of them produce blooms in as few as 55-65 days from seed. The disadvantage to these smaller varieties is that often their flower heads are somewhat drooping. But this is usually not a problem when the flowers are cut.
Another recent introduction are the ‘pollenless’ Sunflowers. These have been produced in dwarf, branching and large-sized flowers. Pollenless Sunflowers produce no male pollen but only fertile female flowers. Pollenless flowers do not shed yellow pollen which can stain and also sometimes results in allergic reactions or might aggravate asthma sufferers. The flowers still produce seed but the female flowers are fertilised by pollen from another male pollen-producing Sunflower. Pollenless cultivars include: Italian White, Lemon Aura and Moonlight are all fine branching forms with nearly white or soft lemon petals; Infrared, a lovely mix of red shades on branching plants; Fantasia, a remarkable pollenless selection of coloured, frilled, fringed and zonal combinations on branching taller plants; Premier F1 in soft yellow; Sunny, large yellow flowers; Petite Bouquet F1 is a similar pollenless series but with more pastel shades on very dwarf plants only 60cm/2ft; lovely Pro Cut Orange F1 produces deep golden double rows of short petals around a dark centre on a robust non branching plant about 160cm/5ft.
The finest truly double forms are Giant Sungold 100cm/40in. and shorter and smaller Teddy Bear 70cm/28in with flower discs up to 13cm/5.2in. With proper care and feeding Giant Sungold can produce heads even bigger on taller plants. These distinctive flowers are in a rich, golden yellow shade. Their petals are thin, and pointed; sometimes almost filaments nearer the flower centres. Flowers are fully double creating a flattened pompon that is almost fuzzy in texture and most striking and very unique in appearance. Plants are stocky but shorter than many other varieties. They benefit from staking as flower heads can become top-heavy if subjected to heavy rain and/or wind at flowering time.
Somewhat less common but highly dramatic and interesting are the brightly coloured hybrid Sunflowers. These produce either short and rounded, sometimes fluted or wavy ray petals in many shades of bronze, copper, cream, orange, pink, nearly red, every shade of yellow and white that often form rings that resemble an archery target. Plants are branching, fast-growing, robust and strong. Usually one large flower is produced at the top followed by numerous strong side shoots with many smaller flowers popping up along each stem. Seeds are small and often dark to ebony black and highly prized by birds.
Floristan F1, Indian Blanket and Ring of Fire are branching classic bicolours 100cm/40in or more with bronze/coppery-red nicely-formed petals with yellow tips and an inner yellow disc around a dark brown centre, creating the impression of a fully eclipsed Sun and corona pattern. Crimson Queen is branching and taller with many bright copper orange near crimson large flowers with shorter petals. Evening Sun is similar with flowers in shades of brick red, bronze, burnt red, copper, to mahogany. Chianti, Moulin Rouge F1 and Prado Red are deep and dusky red shades on branching, tall plants producing many pollenless flowers that are ideal for cutting. Bohemian Rhapsody F1 and slightly taller Fantasia F1 are pollenless mixed collections in many bi and tri-colour and zonal patterns and pastels on branching plants.
All annual Sunflowers are fast growing if planted/sown in rich, moist, deeply dug soil in full sun and sheltered from the worst winds. Plants take about 12 weeks/3months to reach seed maturity. They usually begin to flower at about 2 months (60-70 days) when planted from seed. Dwarf varieties can bloom in as little as 50 days. Sowings can be made any time once air and soil temperatures remain above 50F/10C degrees. If planted into colder temperatures seed often rots. Ideally, air and soil temperatures should remain at near-tropical levels 70F/21.1C degrees or more.
When planted in Early/Mid Summer in an ideally moist, sunny, warm position the seed will germinate in under a week. Growth will be rapid and plants will bloom in Autumn. These will be robust and stocky plants on somewhat shorter canes. Early plantings often take longer for maturation if air and soil conditions remain cool but these plants will often have taller canes. In mild climates that are relatively frost-free, sowings can continue into Autumn which means that flowering will continue into Early/Mid Winter when colour is scarce. The flower heads may not be quite as large as those grown in the heat of Summer and heavy-headed varieties will need secure staking against heavy rain and wintry gales.
Annual Sunflowers grow with a tap root that can reach 4ft/120cm into the soil. For this reason they are best sown direct where the plants are meant to growth. Any bending, damage, disturbance or twisting of the taproot will reflect in some degree of reduced flowering, growth or overall performance of the plant. Soil should be deeply dug up to 2ft/60cm deep to allow easy and full penetration of this tap root. While plants will grow in shallow soil, they often are not nearly as robust or strong so may be blown over in strong winds. Sunflowers grow well in many soil types from loamy to almost sandy provided they are deeply dug and well draining.
Annual Sunflowers are heavy feeders. They need a balanced supply of minerals and trace elements. For the very best performance add a generous dusting of a well-balanced General Garden Fertiliser (20-20-20) with trace minerals included several weeks prior to sowing their seed. Other Gardeners prefer to use a Slow Release Fertiliser. Water this in thoroughly. Caution, Sunflower roots are sensitive to fertiliser salts that come in direct contact with emerging young roots so make sure all fertiliser is well soaked into the soil at least several weeks prior to sowing.
Sunflowers respond well to soils generously enriched with mature compost and/or well-aged manure and/or dried and well-washed seaweed. In light and sandy land, add greensand and extra Potassium to the soil. While Sunflowers require a balanced and constant supply of minerals, they need more Nitrogen early in their development, then more Phosphorous and Potassium as they set buds, bloom and develop their seeds. For this reason some Commercial Growers will use a fertiliser with an NPK ratio of 5-2-4. Soil pH can range between pH 5.5 - 7.5. Lime any soil with a pH below 6.0 for best results.
Seed is usually sown about 1in/2.5cm deep with 5-6 seeds sown in a cluster about 6-8in/15-20cm apart. Always guard freshly sown Sunflower seed and seedlings from hungry birds, rodents, Slugs and Snails! Once these Sunflower seedlings reach 3in/7.5cm tall, thin out to the best 3 or 4. At 1ft/30cm thin these out to two. At 2ft/60cm thin again to the strongest plant. Give plenty of space between plants. 1m/3.34ft or more between plants is not excessive. Plants may still produce large flowers when planted closer than this but will be weaker and flower size will probably be reduced. Plants given much more room can become so immense that they require staking so that their flower heads do not cause the growing cane to collapse.
Sunflowers require plenty of water for best results. Water the seed bed well at first sowing to get them off to a strong start. But then refrain from extra watering until the seedlings emerge unless the ground becomes too dry. Excessive watering at germination can sometimes cause the splitting seed case to collect water and rot the seed germ especially if temperatures become too cool at night. Once seedlings emerge feed and water them regularly. The best approach is to use a dilute liquid fertiliser like Fish Emulsion or Compost/Manure Tea. 1gallon/3.8litres of dilute liquid fertiliser per week would not be excessive.
Liquid feeding is best applied around the Sunflower cane as opposed to directly contacting the cane. Excessive moisture on the cane can lead to rotting. Exhibition Growers often dig a small moat ring about 18-24in/37.5-60cm in each direction away from the cane. The liquid fertiliser solution is filled into this moat as is all watering. Plants can also be mulched if conditions remain excessively dry but this mulch should not touch the cane. Another approach, especially effective in drier positions, is to drive a hollow pipe approximately 2ft/60cm into the ground and regularly fill this with water and dilute liquid manure.
Sunflowers are generally stout and sturdy, especially the medium branching types and dwarf varieties. But be prepared to stake Sunflowers that are taller, especially in positions that might be exposed to heavy rain and/or strong winds. As they grow taller and large flower heads open, the plants will become top-heavy, especially as the flower heads and seeds develop. Avoid deep watering whenever severe or windy weather is forecasts to avoid the threat of the plants being uprooted in soft soils.
If the sunflowers are being grown for exhibition or seed, it is essential to cover the heads as soon as flower petals begin to shrivel, if not even earlier. Birds are most impatient to eat Sunflower seeds even when they are green and will quickly ruin a seed head meant for exhibition. The entire head can be wrapped in a collar of brown or newspaper or covered with a loose-fitting paper bag with some air holes punched in its sides to maintain sufficient air circulation to avoid mildew or mould. Some Growers cover Sunflower heads with netting. But this is best avoided as Birds will often peck right through the netting and may also become entangled within it and die.
Sunflower seed heads are ready to harvest once the kernels are firm and hard and the outer protective floral tissue easily falls away. Harvest either the entire plant or at least a long length of cane with the flower head intact. When meant for seed harvest, hang this, preferably upside down in an airy and well-ventilated, bright (but not sunny) position that remains dry (preferably with lower humidity). Protect the heads from rodents! Leave the heads there for several weeks until the entire head is rather crispy and dry. Seeds can then be easily removed for storage in an airy, dry low-humidity container.
Commercial Sunflowers fields are grown very similar to the method for growing commercial row crops of Corn and Maize. They are then harvested with the same Corn Picker machinery but modified with a special Sunflower harvesting plate attachment. Usually Edible and Oil Seed Sunflowers are harvested once flowers finish and turn brown and dry out sufficiently for the hard seed kernels to begin to fall away when pushed.
Sunflower seeds, especially of Helianthus annus, are baked and roasted or eaten raw. They are very high in minerals and proteins as well as complex carbohydrates. The ground meal is sometimes used as flour similar to Rye flour to make Sunflower (whole grain) bred which is quite popular in Europe. The ground or hulled seeds are often mixed with poultry food or fed to parrots. Sunflower meal is a highly nutritious feed for livestock. The oil cake is used for fattening cattle.
When seeds are dried and crushed, valuable oil is extracted, the finest of which is equal to Olive oil. The meal can be rendered into Sunflower butter, something like Peanut Butter. Cruder forms are used for lighting, woollen dressing, soaps and candle making. Sunflowers also produce a type of latex which is hypoallergenic. Sunflower seed oil is quite good for use in diesel engines. New technology has recently discovered cost-effective ways to extract Hydrogen from this oil, making it potentially very useful and suitable for use in Hydrogen cars.
Sunflowers plants grown in succession sowings around the garden, also make an effective insect control, which is ironic because the growing plants can be eaten by a variety of Beetles, Caterpillars and Grasshoppers. Sunflowers when in flower and especially in seed, attract Finches and other protein-feeding Birds that adore these protein-rich seeds. The Birds not only eat the rich seeds but usually hang around the garden long enough to eat most of the Beetles, Caterpillars and other insects as well, thus eliminating the need for toxic spraying.
Sunflowers have also proven to be very useful in decontaminating toxified soils, especially those containing arsenic and lead. When planted in large fields below a water-shed, they are excellent for filtering contaminated water. They have been used successfully to detoxify land around Chernobyl that had been toxified with Uranium.
There are also many perennial forms of Sunflower. Most all of these are various forms of bright yellow daisy flowers produced either singly or in clusters atop wiry stems over dark to medium green, sometimes course foliage. The best known is perhaps Helianthus salicifolius ‘Autumn Glory’ or ‘First Light’ commonly known as the Willow-Leafed Sunflower. This is a perennial herb with a very bushy habit 1-2m/3.34-6+ft tall and often nearly as broad. In Late Summer and Autumn the plants are completely smothered with bright golden yellow daisies about the diameter of a small Orange. These usher in the early days of Autumn and are an absolute magnet to Bees, Butterflies and Hummingbirds. After flowering, the plants conveniently die away and reliably reappear the following Spring.
Many other perennial Sunflowers make really showy plantings at the back of a sunny border. Helianthus giganteus, the Indian Potato or Wild Sunflower is very tall and dramatic rising on stout canes to 12ft/3.4m that branch producing loose flower heads of pretty yellow Sunflowers about 7-8cm/3in across. It is a hardy and reliable wildflower for the back of the perennial border, meadow, prairie or wildflower garden.
In somewhat drier positions, very similar H. Maximiliani often takes its place.
Helianthus angustifolius, the Swamp Sunflower, grows to 2 1/2m/8.4ft or more; while H. decapetalus, River Sunflower or Thin-Leafed Sunflower, is a little shorter. Both thrive in moist soils, even swamps. But they are not particular to soil enrichment and are often found on waste land that remains moist or wet during their period of growth but can dry out as they flower later in Summer and Autumn. These species both feature large, lance-shaped leaves that curtain the strong, tall cane-like stems crowned with large flowers clusters in a clear, bright yellow about 2-3 in. across. The overall effect is somewhat similar to a grove of Bamboo canes over-spread with a canopy umbrella of deep green foliage sparkling with a crown of golden yellow daisies.
H. tuberosus looks similar but is more robust, taller, and hardy to a variety of growing conditions. The overall effect is a leafy grove of stout canes topped with a loose arrangement of yellow daisy flowers. H. Tuberosus is also known as the Jerusalem Artichoke or Canadian Potato. This valuable wild American species was widely cultivated by the American Indians for its edible tubers. These taste like Potato or Yam and can be left in the ground all Winter being harvested as needed. They are very easy to grow! The Jerusalem Artichoke is a wonderful addition to either the annual or perennial border as well as in the background of the vegetable garden. This is one of the hardiest and most reliable of perennial vegetables that can be allowed to multiply and spread for years undisturbed.
Sunflowers, especially the annual varieties and shorter perennial species are quite suitable to container growth. The perennials types like Helianthus ‘Autumn Glory’ thrive in larger tubs or landscape planters and terraced beds provided they can be kept continually moist but freely draining. Their extensive root system precludes their use in all but larger containers.
The annual Sunflowers demonstrate a remarkable ability to accommodate containers of almost any size. Even the larger species will naturally dwarf to suit the size of their container. In recent years, a variety of truly dwarf forms have been developed that are ideally suited to this purpose. They are often sold in the Florist and Nursery Trade as most attractive if somewhat short-lived ornamental container plants. Because of their quick germination, rapid growth, easy cultivation and dramatic flowering they make an ideal pot plant for children of any age.
Choose a pot with generous drainage holes and fill with a good quality potting mix enriched with slow release plant food. Lightly cover several seeds with mix and keep moist in a bright, sheltered and warm environment. It is important to maintain a constant and even supply of moisture and liquid feed on a regular (weekly) basis. They are so easy to start and grow to flowering often in as little as 50-60 days. Sow a few pots every couple of weeks for a continuous show of sunflower colour all Summer and Autumn or even in the glasshouse throughout the Winter months.
Amongst the best and easiest Sunflowers for container culture are the colourful and most unique zonal dwarf species such as Petite Bouquet F1 and fully double dwarf Teddy Bear. And for a classic golden yellow Sunflower in a truly dwarf size try: Munchkin F1 60cm/2ft which is pollen-free with a green centre; ‘Incredible Dwarf at only 45cm/18in. is very fast-flowering and pretty with large and long petals like larger relative, Royal Crown; Sunspot features enormous 20-25cm/8-12in. flowers on stocky 45cm/18in plants that branch to produce extra blooms down the stem; or for something even shorter at only 30cm/1ft try Big Smile.
Truly, Sunflowers have earned the adoration and respect of Gardeners around the world since antiquity. There is no other flower in Nature that so aptly lends itself to represent our appreciation, dependence, love and praise for the Sun than the treasured Sunflowers.
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