The Latin name is helianthus annuus, and just as the common name means flower of the sun; as everyone knows, sunflower is a particular flower, which with its large disc follows the sun throughout the day, so as to receive direct sunlight for as many hours as possible. Although it is now a widespread plant in much of the globe, both in cultivation and as a wild plant, the genus helianthus includes only species originating from the American continent. Helianthus were cultivated for food purposes already millennia ago, by the Aztecs and the Incas, and therefore there are very many hybrids and cultivars, which have very ancient origins. The introduction in Europe happened already in 1500, and therefore these plants have had some centuries of time to spread in our continent, where they began very soon to be cultivated, mainly to exploit the oil contained in the seeds. The sunflower is not exactly a flower, as happens with all asteraceae, it produces a large inflorescence, where the small flowers are close to each other, in a spiral pattern; the flowers inside the disc are tubular, those on the outside carry one or more petals, forming a sort of broad corolla. The tubular flowers, after pollination, produce a large seed, covered by a thin woody shell; from these seeds a highly appreciated oil is obtained, but they are also consumed after being toasted, as they are or added to salads, bread, desserts.
The sunflower plant
Obviously in cultivation there are many hybrids; the real sunflower, helianthus annuus, is an annual plant, as its name suggests. It produces a rigid, erect, well developed, poorly or not at all branched, tall stem, up to 2-3 meters high; at the apex the large inflorescence blooms, which becomes of enormous dimensions in the varieties cultivated to produce oil from the seeds. In the garden dwarf species are placed as dwellings, where the stems do not exceed 70-120 cm in height; the flower is produced in the summer. The plant also has large heart-shaped leaves, and is very pleasant in the garden. There are also numerous cultivars that produce many small flowers from each individual stem, or even perennial species, such as Helianthus multiflorus, or Helianthus rigidus: small messy and well-branched shrubs, dense, which are covered with daisy-colored flowers throughout the summer gold.
Cultivation helianthus annuus
They are not plants of difficult cultivation, they produce deep, fictitious roots, which therefore need a good deep and rich soil in order to develop better, well worked and enriched with mature manure. Obviously they need to be planted in a very sunny place, or the flowering will be scarce and the plant will tend to perish easily.
Perennial species are available in nurseries as small plants, to be planted directly in the garden, generally they do not fear frost and remain alive and vigorous for some years; the annual species, on the other hand, are sown in seed beds or directly in their homes.
They do not need special care, if not some watering in dry periods; sunflower plants can withstand a few dry days, but tend to wither when the drought lasts for too long, in these cases it is sufficient to water them abundantly for the plant to recover. We avoid however to leave the plants in a heavy and constantly damp ground. The vigor of sunflowers, the quite significant root system, and the great production of seeds, make them quite invasive over time; It is therefore good to place them in a pretty confined flowerbed in the garden, or to pick up the withered flowers, to prevent the seeds from scattering randomly in the garden. The perennial species, over the years, are more floriferous if they are periodically eradicated, divided and repositioned in a rich and fresh soil. We therefore avoid leaving our plant in the flowerbed for years; in autumn, every 3-4 years, we remove the entire plant, let's enrich the soil with fresh and manure soil, and reposition the shrub, or part of it if we want to divide it.
Sunflower - Helianthus annuus: A sunflower rich in qualities
Among the many species of helianthus, one in particular is also cultivated in the garden, is the helianthus tuberosus, better known as Topinambur; it is a perennial species, which produces tuberous roots, similar to large lumpy potatoes. The Jerusalem artichoke tubers are eaten raw or steamed, and are particularly suitable for diabetics, as the starch they contain is not digested and help to regulate the amount of insulin in the blood.
As with all other sunflowers, these are also cultivated in a very bright and sunny place; they produce a shrub up to 150-180 cm high, fairly branched, which is filled in summer with yellow daisies. The tubers are harvested at the beginning of autumn, and generally the smaller ones are left to stay for the following year's production.
Jerusalem artichokes are also widespread as wild plants, and can be found in uncultivated fields, at the edge of the woods, in hilly pastures.