Sweet Potato Leaves
Estimated Inventory, lb : 0
Description/Taste
Sweet potato leaves vary in size and shape, depending on the specific variety and age at harvest. The leaves appear heart-shaped, triangular, round, or tapered, and some varieties have multiple lobes ending in pointed tips. Sweet potato leaves grow upright and have a pliable, floppy, and delicate nature, being easily torn or broken. The leaf’s surface is typically covered in prominent, branching veining, giving the surface a soft, smooth to slightly crinkled feel. The leaves also range in color from purple, yellow-green, bright green, to dark green, depending on the variety. Most leaves will be lighter on their undersides and bear lighter-colored stems. The stems are firm, crisp, aqueous, and snappy with a succulent consistency. Once cooked, the stems and leaves become soft, tender, and subtly chewy. A few varieties may also have a slippery texture. Sweet potato leaves are only eaten cooked and have a mild, vegetal, sweet, subtly bitter, and neutral taste reminiscent of cooked spinach.
Seasons/Availability
Sweet potato leaves are available year-round, with a peak season from April to November.
Current Facts
Sweet potato leaves, botanically classified as Ipomoea batatas, are the foliage of herbaceous perennial vines belonging to the Convolvulaceae family. Historically, the species has been known for its underground tubers and has been planted worldwide as an essential famine crop. Sweet potato leaves were mostly regarded as a secondary crop to the tubers, and for many years, the young and tender foliage was consumed as food for low-income families and livestock. In the 20th century, the leaves began to be promoted as a nutritious green, leading Sweet potato leaves to become a popular commercial crop throughout Asia. Sweet potato leaves for culinary use have been traditionally harvested from plants when the leaves are young, but these varieties require the leaves and stems to be cleaned and the stalk membrane removed, making them a time-consuming ingredient. These early versions also have rougher leaves with a less favorable flavor. In the late 20th century, various breeding programs throughout Asia began developing varieties only grown for their leaves. In Taiwan, Tainong No. 2 and No. 71 are the two most famous sweet potato leaf varieties. Both cultivars do not produce underground tubers and have the capacity to grow tender Sweet potato leaves year-round. Modern Sweet potato leaves are found in varying colors, shapes, and textures. The plants are fast-growing and have become a prevalent crop in commercial markets worldwide, especially in Asia. Sweet potato leaves are utilized in cooked preparations and have a mild flavor that can accompany a wide array of ingredients.
Nutritional Value
Sweet potato leaves are a source of vitamin C to strengthen the immune system, fiber to regulate the digestive tract, calcium to protect bones and teeth, and iron to develop the protein hemoglobin for oxygen transport through the bloodstream. Sweet potato leaves also provide vitamin A to maintain healthy organ functioning, vitamin K to assist in faster wound healing, potassium to balance fluid levels within the body, magnesium to control nerve operations, and other nutrients, including zinc, manganese, vitamin E, and B vitamins. In Traditional Chinese Medicine, the leaves are viewed as a cleansing ingredient, increasing bowel movements and lubricating the lungs and intestines.
Applications
Sweet potato leaves have a mild, sweet, vegetal, and subtly bitter flavor suited for fresh and cooked preparations. Before cooking, the leaves should be washed well and roughly chopped or torn into smaller pieces. It is also important to note that the leaves may discolor and sometimes turn black due to their high iron content. This can be lessened by cooking with lemon juice or blanching the greens and mixing them with garlic soy sauce to add a different color to the dish. Sweet Potato leaves have a texture and flavor like spinach and can be prepared similarly, sauteed, blanched, steamed, or stir-fried. In Asia, Sweet potato leaves are popularly cooked with aromatics such as garlic, shallots, or ginger as a simple side dish. Sweet potato leaves can also be simmered into soups, curries, and stews, braised in coconut milk, or sauteed with other vegetables. If the leaves are being boiled, the cooking water may be reserved for later use as a slightly bitter broth or as a health drink, as the water will contain nutrients from the leaves. Try cooking Sweet potato leaves into noodle or rice-based dishes. They are also often stir-fried with dried fish in Asia for a distinct flavoring. Sweet potato leaves pair well with meats such as chicken, beef, pork, or fish, red bell peppers, tomatoes, broccoli, mushrooms, and water chestnuts. The leaves are highly perishable and should be immediately consumed for the best quality and flavor. Sweet potato leaves will only keep for a few days or up to one week, depending on their age, when loosely wrapped in a damp paper towel and stored in the refrigerator.
Ethnic/Cultural Info
Sweet potato leaves are one of the most popular cooked greens in Taiwan. The leaves and stems have been selectively bred to create varieties specifically used for their greens, and sweet potatoes, in general, are cultivated across Taiwan. In Chiayi, the Root Crop Research Laboratory is one of Asia’s largest sweet potato seed banks, preserving over 1,400 varieties. The laboratory is nicknamed the “Cradle of Sweet Potatoes” in Taiwan and stores seeds from varieties developed domestically and internationally. Beyond the species’ widespread presence in Taiwan, Sweet potato leaves are also being creatively incorporated into unusual preparations. The leaves are blanched, blended with water and fruit such as apples or pineapples, and made into a drink. This beverage can be served hot or cold and is nicknamed a “green latte.” Select Sweet potato leaf varieties are also dried and made into a specialty tea. One of the more unique innovations is cooking chopped Sweet potato leaves in a soy sauce and mushroom water mixture to make a seaweed substitute. The cooked leaves are molded into a rectangular shape like dried seaweed and are called “Taiwan Moss.” This seaweed substitute is beneficial for consumers who suffer from hyperthyroidism and typically cannot consume seaweed.
Geography/History
Sweet potato leaves are native to South America and have been growing wild since ancient times. Ipomoea batatas, as an overall species, has been cultivated throughout civilizations in the Americas for thousands of years and has been selectively bred to create improved varieties. Sweet potatoes were later introduced to Europe and Asia through exploration and trade, and they were first planted in China sometime during the Ming Dynasty, from 1368 to 1644 CE. From China, sweet potatoes eventually made their way to Taiwan, possibly around the 17th century, and the tubers and leaves were initially consumed as a famine food and livestock feed. In Taiwan, sweet potatoes were once called the “pig vegetable” for their use as animal feed. Original sweet potato varieties had coarser, rougher, and tougher leaves, making them time-consuming to prepare. In 1987, the Taoyuan District Agricultural Improvement Center in Taiwan successfully bred a new variety of sweet potato that is only cultivated for its leaves. The variety was called Tainong No. 2 and saw success throughout Taiwan by 1998. The Chiayi Agricultural Experimental Branch also developed another variety, Tainong No. 71, making these two varieties the most commercially successful for solely their leaves. Today, Sweet potato leaves are cultivated worldwide. The leaves as a culinary ingredient are mainly consumed in Asia, especially in Taiwan, and are sold fresh through local markets, supermarkets, and select distributors.
Recipe Ideas
Recipes that include Sweet Potato Leaves. One
is easiest, three is harder.
