Choy sum, a green leafy vegetable that is never absent from a typical Cantonese dining table, roughly translates to "heart of the vegetable" in Cantonese. It is called "caixin" in Mandarin and is a member of the mustard family under the genus Brassica.

This simple green vegetable is native to China's southern province of Guangdong. It has been in the yards of the Cantonese since the 11th century.

Choy sum is pervasive in temperate zones. It thrives in regions where temperatures are between 15 and 25 degrees Celsius. Once the temperature is above 25 degrees, the sweetness of the choy sum would turn slightly bitter.

Green vegetables play a crucial part in traditional Cantonese cuisine. And choy sum is a signature green vegetable among others in Guangdong. The Cantonese love to cook it by scalding it, which is one of their favorite ways of cooking: burning raw food with boiling water. 

This way the freshness and original flavor of the food can be preserved. After scalding, the choy sum is served with oyster sauce or a small portion of scallion to bring out the flavor.

Although native to Guangdong, choy sum has found its second home in northwestern China's Ningxia Hui Autonomous Region. The drastic temperature difference between day and night, along with the irrigation from the Yellow River, has made it suitable for the vegetable to grow and accumulate its sweetness.

Now, the vegetable's pickers in Ningxia pick around 18,000 choy sums per day. These fresh vegetables will travel thousands of kilometers to the tables of choy sum lovers in the south.

From the wetlands along the east coast to the dense rainforests hidden in the west, China boasts an array of plant species. In this series, CGTN takes you on a tour to learn about some of the most representative flora in different provinces and see how they live in harmony with the local geography and climate.

(Cover: VCG, designed by CGTN's Jia Jieqiong.)

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