Sweet potato According to relevant public information, due to the cold weather in the north, many vegetables in winter are not very fresh, so many people will pickle a lot of pickles before winter, so in the north, you can almost see that every family has food and pickles are placed on the table. Among many pickles, one is commonly known as "Le Er", which looks like a gourd, so it is also called sweet gourd. It is an annual or perennial herb, which can form underground tubers in Stachys of Labiatae. Originated in the north of China, it was cultivated and utilized as early as17th century, and now it is cultivated all over the country.