Tay Ninh province, along with other southern provinces in Vietnam, is famous for a unique vegetable that leaves an unforgettable impression on anyone who has tried it – the Cosmos caudatus, commonly known as “rau sao nhái” in Vietnamese. In the past, this vegetable used to grow wild along roadsides, in fields, home gardens, or on damp land. People often pulled it out without realizing its value. However, nowadays, rau sao nhái has become a delicacy favored by many due to its distinct and memorable flavor.
Rau sao nhái, also known as rau nhái, rau sao nhái rừng, or cúc chuồn, is scientifically named Cosmos caudatus and originates from the tropical regions of South America. Belonging to the Asteraceae family, rau sao nhái can be categorized into three main varieties: pink Cosmos caudatus, purple Cosmos bipinnatus, and yellow Cosmos sulphureus. The pink variety, Cosmos caudatus, is the most popular among the three due to its higher nutritional content.
The flowers of rau sao nhái usually grow singly or in clusters at the top of the plant. Each flower has eight petals and a bright yellow pistil in the center. The plant can grow to a height of 30 cm to 2 meters, sometimes even reaching 3 meters. It has an upright stem, growing in bushes, with light green leaves tinged with purple. The leaves are trifoliate and arranged alternately like spears, with petioles measuring 10 to 20 cm in length.
The rau sao nhái plant can grow to a height of up to 2 meters and sometimes even taller
The leaves of rau sao nhái emit a subtle fragrance and remain tender at any age, and they are edible. This vegetable is commonly used raw, paired with other wild vegetables, or wrapped in rice paper with grilled pork. It is also a perfect match for dishes like fish stew, fermented fish, or meat stew. When eaten raw, rau sao nhái has a sweet and slightly sour taste with a hint of bitterness. When boiled or stir-fried, it offers a rich and savory flavor.
Apart from its unique flavor, rau sao nhái is also a nutrient-rich source of vitamins A and C, polyphenols, and antioxidants, offering various health benefits. Specifically, it helps purify and enrich the blood, combats aging, and prevents osteoporosis. However, it is essential to distinguish rau sao nhái from a similar-looking flower called “hoa sao nhái” or “butterfly flower.” The latter is primarily grown for ornamental purposes and has larger flowers and non-edible leaves that lack the distinctive fragrance of rau sao nhái.
Be cautious and refrain from picking or consuming hoa sao nhái to avoid potential health risks
To start growing rau sao nhái, you can purchase seeds or seedlings from a store. If using seeds, simply scatter them on moist soil, cover lightly with a thin layer of soil, and maintain moisture. Alternatively, if you don’t have access to seeds or seedlings, you can propagate through stem cuttings. Choose a mature rau sao nhái plant, cut a 15-20 cm long stem section, and plant it in the soil, ensuring that at least one or two nodes are in contact with the ground.
Within one to two weeks, the seeds or cuttings will sprout and take root. When caring for rau sao nhái, consider the following factors:
– Soil: The plant thrives in well-drained, nutrient-rich, loose soil. Mix organic matter or compost into the soil. If space is limited, consider growing it in pots or containers.
Mix organic matter or compost into the soil to provide adequate nutrition
– Light: Rau sao nhái prefers full sun. If growing in pots, choose a location that receives morning sun and afternoon shade to prevent scorching.
– Watering: Maintain soil moisture but avoid waterlogging. Water regularly, especially during hot and dry periods.
– Fertilizer: Once the plant starts producing young leaves, provide additional nutrients using organic fertilizer or NPK fertilizer on a monthly basis.
With proper care, the plant will grow vigorously and produce young leaves within one to two months. When the plant reaches a height of about 30-40 cm and has young leaves, you can start harvesting the leaves for consumption.
The Wild Weed: From Roadside Nuisance to Delicacy and Ornamental Delight
This vegetable has a delicate fragrance and a tender, edible texture, whether young or old.
