When was the earliest recorded planting of medicinal plants?

China has a long history of planting medicinal plants and accumulated rich experience. As early as 2,600 years ago, the Book of Songs recorded the cultivation of dates, peaches and plums. By the time of Emperor Wu of the Han Dynasty 2000 years ago, the production of medicinal materials had begun to take shape, and an introduction garden was established in Chang 'an. Zhang Qian went to the Western Regions and introduced plants with medicinal value such as safflower, pomegranate, walnut and garlic to the mainland for planting, thus enriching the varieties of Chinese herbal medicines. In 1960s, Jia Sixie wrote Qi Yao Min Shu, describing the cultivation methods of medicinal plants such as Rehmannia glutinosa, Carthamus tinctorius, Evodia rutaecarpa, ginger, Gardenia, Mulberry, flax and lotus. In 58 1-6 18 of the sui dynasty, the positions of "main medicine" and "medicine gardener" were set up under the Chinese medicine department, in charge of planting medicinal materials. There are also monographs such as "Plant Medicine Law" and "Plant God Grass" in Sui books. In the Tang and Song Dynasties, the cultivation technology of Chinese herbal medicine had an unprecedented development, and the cultivation methods of medicinal plants such as lily and garlic were recorded in Fang Yi in the advance of the Tang Dynasty. In the Song Dynasty, Han Yanzhi described dozens of Chinese herbal medicine planting methods such as orange, loquat, rosewood and Polygonatum sibiricum in "Orange Record". In Ming Dynasty, Li Shizhen recorded 180 planting methods of more than 80 kinds of Chinese herbal medicines in his medical masterpiece Compendium of Materia Medica. His works on materia medica and agronomy include Wang's Genealogy of Family Rooms in Ming Dynasty, Xu Guangqi's Encyclopedia of Agricultural Administration in Qing Dynasty, Chen Fuyong's Flower Mirror and Wu's Textual Research on Plant Names and Facts. Among them, the cultivation of various medicinal plants is discussed, which is still of reference value. According to statistics, there are more than 200 kinds of medicinal plants introduced and cultivated by working people in past dynasties in China. It can be said that most of the main varieties planted today are laid by our ancestors. Ancient works, as our cultivation techniques today, provide valuable scientific data.