Helianthus annuus ‘Orange Sun’: Unveiling Its Stunning Features and Uses

The Helianthus annuus ‘Orange Sun’ is a medium-height sunflower, standing 1 to 3.5 meters tall. Mimicking the sun in appearance, its flowers are bright and generous, averaging 13-15 cm in width, ideal for ornamental display.

They bloom in the summer, with yellow tongue-like flowers growing around the edge of the inflorescence, but do not bear fruit.

Its seeds have greater economic value, not only can they be made into popular sunflower seeds, but they can also be pressed to produce high-quality, low-cholesterol sunflower oil.

I. Morphology and Characteristics

This is an annual herb, 1.0 to 3.5 meters tall. Some hybrid varieties have half-meter tall plants. The stem is upright, robust, multi-angled, and covered in coarse white hair.

Leaves typically grow alternately, heart-shaped or ovate, acutely or gradually pointed at the tip, with three veins at the base. The leaf edge is coarsely serrated, rough on both surfaces, hairy, and has a long stalk.

The capitulum is extremely large, with a diameter of 10 to 30 cm, growing singly at the top of the stem or branch, often drooping. The involucre is multi-layered, leafy, arranged like roof tiles, and covered in long, stiff hairs.

It blooms in summer, with yellow tongue-like flowers growing around the edge of the inflorescence, but does not bear fruit. The central part of the inflorescence has bisexual tubular flowers, brown or purple, that bear fruit.

The achene is an inverted ovate or oblong egg shape, slightly flattened, with a woody pericarp, gray or black, commonly known as sunflower seeds. The most common height for sunflowers is 2.5 to 3.5 meters.

According to scientific literature from 1567, the tallest single-headed sunflower plant on record, grown in Padua, reached up to 12 meters. The same seeds grown at other times and places (like Madrid) can reach nearly 8 meters in height.

II. Lifestyle Habits

Sunflowers originated in the tropics, but they have a strong adaptability to temperature and are a warm and cold-resistant crop.

Sunflower seeds are highly cold resistant; as long as the ground temperature is stable and above 2°C, the seeds begin to sprout; at 4-5°C, the seeds can germinate and root; when the ground temperature reaches 8-10°C, it can meet the needs of seed germination and seedling emergence.

The optimal germination temperature is 31-37°C, and the maximum temperature is 38-44°C. As long as the temperature during the entire growth process is not below 10°C, the sunflower can grow normally.

Within the suitable temperature range, the higher the temperature, the faster it develops.

III. Cultivation Method

Soil Selection

Apart from soil that is prone to flooding, pure sand, or excessively saline-alkali, sunflowers can be planted in various types of soil with a pH value of 5.5 to 8.5.

However, loamy or sandy loam soil with a pH value of 6.0 to 7.2 and higher fertility is optimal. Sunflowers have strong salt tolerance.

They can grow normally and yield high in chloride or sulfate salt soil with a total salt content of <1%, and soda saline-alkali soil with a total salt content of 0.3% to 0.4%.

To prevent bird damage, avoid planting near forests; to prevent pesticide smell from affecting bee activity, try to plant far from vegetable fields.

Crop Rotation

Sunflowers are not strict about the previous crops. Legume crops, corn, wheat, sorghum, and millet are all good options, but legume crops should not be infected with sclerotinia.

In areas with severe occurrence of wilt and sclerotinia, deep-rooted crops like potatoes, tobacco, beetroot, and alfalfa in the Solanaceae family should not be the preceding crops for sunflowers.

Sunflowers should not be continuously cropped, and the minimum rotation period is 3 years. For plots severely affected by downy mildew and sclerotinia, the rotation period should be over 8 years; for those severely affected by gray mold, over 6 years; for those severely affected by sclerotinia, over 4 years.

For saline-alkali land, due to special needs for soil improvement, continuous cropping can be allowed for 2 to 3 years.

Deep Ploughing and Land Preparation

In the autumn, carry out deep ploughing or loosening to depths of 20-25 cm or 30-40 cm respectively. If the soil layer is thick, the soil texture is sticky, and the land is saline-alkali, deeper ploughing might be required for better loosening effects.

After loosening, harrow in time. Deep ploughing (loosening) is generally carried out once every 2-3 years. Deep ploughing is a fundamental measure for improving saline-alkali land.

For land with heavier saline-alkali content, first irrigate to wash away the salt before ploughing.

Saline-alkali land with sticky soil and many clods requires repeated harrowing, especially late spring harrowing can effectively suppress the rise of saline-alkali. Saline-alkali land must be levelled to prevent formation of salt spots.

Application of Base Fertilizer

Generally, apply 35-45 tons of farmyard manure per hectare.

IV. Value and Other Uses

The stems and leaves can dispel wind, clear heat, cleanse the liver and brighten the eyes. A decoction of 5 grams of sunflower stems and leaves plus 10 jujubes, taken daily for 5-7 consecutive days, can treat hypertension.

A decoction of fresh sunflower stems and leaves can treat red and watery eyes.

The stem pith can fortify the spleen, drain dampness and stop leukorrhea. A decoction of sunflower stem pith can treat watery leukorrhea and weak lower back and knees.

A decoction of 20 grams of sunflower stem pith, 5 grams each of wick, bamboo leaves, and couchgrass, can treat gonorrhea and prostatitis.

The roots can clear heat, drain dampness, move qi and alleviate pain. A decoction of sunflower roots can treat frequent urination, urgency, and pain due to gonorrhea. A decoction of 30 grams of sunflower roots and 10 grams of atractylodes can treat gastric pain.

The flowers can clear heat, detoxify, reduce swelling and alleviate pain. A decoction of sunflower flowers in half wine and half water can treat mastitis.

Crushed fresh sunflower flowers or dry powdered ones mixed with sesame oil can treat boils, carbuncles, mastitis. The liver can expel wind, clear damp heat, and reduce stagnant qi.