Sweet potatoes were brought by the Spanish from South America to Europe after the conquest of Francisco Pizarro González, Marquess of the Atabillos in 1532.
Sweet potatoes have been grown in the United States since 1648, when they were first planted in Virginia. They were grown by the American Indians in the 18th century and were introduced to New England in 1764

The sweet potato is not native to Japan. Originally it came from Central South America. Then in 1605, it came to Ryukyu island (Modern day Okinawa ) during the Ryukyu Kingdom (1429 – 1879)  via Noguni Sokan, a government official from Noguni Village (part of present-day Kadena Town), is credited with bringing and cultivating sweet potatoes from Fujian of Ming (present-day China).  The Spanish brought the Sweet potato from South America  to Spain and onto India then it made its way to the Philippines, China and then to Okinawa. . About 100 years later, in 1705, it started to spread widely in Kagoshima.
Even though the Satsuma Imo only arrived about 300 years ago, it was so well suited to Kagoshima’s climate and environment that it spread extremely quickly. Because it grew so quickly, during a famine in 1732, Satsuma Imo saved many people from starvation and it was so valued.
The people so identified with the newly introduced crop that they began to call it the Satsuma Imo. Even though it is given one name, the Satsuma Imo varies greatly in color, flavor, and starch content.