The Rape Flower, also known as Brassica rapa, is a native plant of Europe and Central Asia. This annual herbaceous plant, a member of the Brassicaceae family, is primarily found in China in areas such as Wuyuan Huangling in Jiangxi, Hanzhong Basin, and Jiangling’s terraced fields, Luoping Plain in Yunnan, and Menyuan Plateau in Qinghai.
It blooms in March and April, with the stem bearing flowers in a racemose inflorescence. The calyx has four yellow-green sepals and the corolla has four yellow petals arranged in a cross shape.
The fruit is a siliqua which, in summer, splits upon ripening to release its purple-black, sometimes yellow, seeds. The Rape Flower is rich in pollen and its seeds contain 35-50% oil, which can be pressed for oil or used as feed. The tender stems and leaves of the plant can also be consumed as a vegetable.
Physical Characteristics
Rape plants grow upright in clusters, with green stems and yellow flowers. The basal leaves grow in a rosette while the stem leaves are usually alternate, without stipules. The flowers are bisexual and radially symmetrical, with four petals arranged in a cross.
The petals are delicate, with subtle striations that no skilled sculptor could replicate. The six stamens are usually arranged with four long and two short, commonly referred to as “four strong stamens”. The pistil is composed of two carpels with the ovary positioned above.
The cylindrical stems, which range in diameter from 0.1-0.8 centimeters, are multi-branched and relatively soft. The leaves are large, dark green, with no petioles or stipules. The fruit is a siliqua which, in summer, splits upon ripening to release its purple-black, sometimes yellow, seeds.
With its four petals neatly encircling the stamens, the Rape Flower is unpretentious yet distinctive. Its stamens cluster together as if whispering secrets. The plant exhibits hardy rhizomes, lush leaves, and an authenticity and robustness reminiscent of the farmers who cultivate them.
Distribution
The Rape Flower is primarily found in areas such as Wuyuan Huangling in Jiangxi, Hanzhong Basin, and various regions along the Yangtze River in China.
Cultivation Techniques
Top Dressing
During the Rape Flower’s blooming period, every few days, spray a water solution of trace elements such as phosphorus, boron, manganese, or a composite organic fertilizer to prevent blooming without fruiting. Spraying a 0.02% boric acid solution can increase the number of effective branches, the number of pods per plant, and the thousand-grain weight.
During the pod maturity period, spray a 2-3% calcium superphosphate water solution.
Watering During Blooming
The blooming period of the Rape Flower lasts up to 30 days and requires a large amount of water. Depending on the soil moisture conditions, water 1-2 times.
Watering During Pod Formation
After the Rape Flower has finished blooming, irrigate appropriately depending on soil moisture conditions. During the pod formation period, water 1-2 times.
Pests and Diseases
The main diseases of the Rape Flower are sclerotinia and viral diseases. Sclerotinia often occurs during the blooming and seed-bearing stages and can be prevented by spraying a solution of carbendazim or polyoxin. Viral diseases can be mitigated by controlling aphids.
To control aphids, use 500 grams of 40% Le Fruit emulsion per acre, diluted with water to 1000-1500 times, or use a 50% anti-aphid wettable powder diluted to 3000-5000 times.
Alternatively, use 50 grams of 50% quick-acting sulfur wettable powder, or 200 grams of 40% disease-killing suspension, mixed with 75 kilograms of water, and spray evenly on the lower stems, branches, leaves, and upper inflorescences of the plant.
Primary Value
Application Value
The Rape Flower is rich in pollen, and its seeds contain 35-50% oil, which can be pressed for oil or used as feed. The tender stems and leaves of the plant can also be consumed as a vegetable.
The Rape Flower is the largest source of edible plant oil in China.
The juice made from Rape Flowers is said to have medical effects in preventing high blood pressure, anemia, and colds.
Economic Value
The development of China’s rapeseed industry makes the Rape Flower one of the most important oil crops in the country, with a seed oil content of 33-50%.
Since 1995, the annual planting area has been around 100 million acres, producing nearly 10 million tons of rape seeds annually, accounting for 40-45% of the total output of oil crops (excluding soybeans) and also producing about 6 million tons of rape seed cake. The protein content of the cake is as high as 40%.
The amino acid composition of rapeseed protein is reasonable, with the lysine content comparable to soybeans, and the content of sulfur-containing amino acids such as lysine and threonine higher than soy protein. It is China’s largest source of high-quality feed protein waiting to be developed and utilized.
In addition to being used for oil extraction and feed, rapeseed can also be used to produce artificial cream and protein in the food industry. It also has a wide range of uses in metallurgy, machinery, rubber, chemicals, paint, textiles, soap, paper, leather, and medicine, and has significant economic value.
Ornamental Value
The Rape Flower has significant economic value and ornamental value, making it a tourism resource. During the Rape Flower’s blooming season, the fields turn a golden yellow, as described in the poem by Yu Shao, “Rape flowers bloom all over the ground, between the clusters, butterflies dance and bees are busy.
The breeze stirs up golden waves, and the rich fragrance intoxicates.” Rape Flowers bloom vigorously, their pollen rich in nectar, attracting butterflies and bees to dance among the flowers. The strong fragrance is intoxicating, and the beautiful scenery is captivating.
Peggie was once a high school mathematics teacher, but she set aside her chalkboard and textbooks to follow her lifelong passion for flowers. After years of dedication and learning, she not only established a thriving flower shop but also founded this blog, “Flowers Library”. Here, Peggie shares the art and science of floristry, offers practical tips for nurturing plants, delves into the captivating histories of various species, and provides insights into running a successful flower shop. She hopes that everyone can take a moment now and then to immerse themselves in the world of flowers. If you have any questions or wish to learn more about flowers, feel free to contact Peggie.
