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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Sweet Potatoes or Yams?

This article was published originally on 11/8/2006

Turkey, dressing, cranberry sauce, and pumpkin pie are all part of a traditional Thanksgiving feast. Candied yams or sweet potatoes are another Thanksgiving favorite.

While sweet potatoes or yams are a holiday staple, the different common names do create some confusion. Are sweet potatoes and yams the same thing? If not, what are the differences? Which is served at Thanksgiving?

In the United States, sweet potatoes are often referred to as "yams." However, sweet potatoes and yams are actually different crops.

Sweet potatoes (Ipomoea batatas) are vining plants in the morning glory family. They are believed to be native to Central and South America. The storage roots of sweet potatoes are short, blocky, with tapered ends. They have a smooth, thin skin. There are two main types of sweet potato. Dry-fleshed types usually have a light yellow skin and pale yellow flesh. When cooked, they are dry and crumbly, much like a baking potato. Moist-fleshed types typically have a dark orange skin, orange flesh, and are moist and sweet when cooked. In the United States, the moist, orange-fleshed types are the most commonly grown sweet potato and are often referred to as "yams."

True yams (Dioscorea batatas) are vining plants in the yam family. They are native to Africa and Asia. Yams are long, cylindrical, underground tubers with a rough, scaly skin. Tubers can be several feet long and weigh 50 pounds or more. Yams are rarely found in the United States. However, they are popular in Latin American countries.

The word "yam" is believed to come from the African word "nyami" (meaning "to eat") for true yams. It is believed that black Africans brought to America during the slave trade began referring to sweet potatoes as "yams" because of their similarity to true yams. Over time, most Americans began using sweet potato and yam interchangeably for the moist, orange-fleshed types of Ipomoea batatas.

Page References: 
114
Year of Publication: 
2006
Issue: 
IC-495(24) -- November 8, 2006