Family: Convolvulaceae
Common name: Sweetpotato, Sweet potato, Edible sweet potato, Sweet potato vine, Batata, Batata doce, Batata hilwa, Camote, Camotli, Apichu, Khumara, Kumala, Madhurakizhangu, Sakkara valli kilangu
Sweet potatoes are eaten as vegetables all over the world, in tropical and temperate countries, only slightly less popular than Potatoes. Though they have the same name, these plants belong to different families, Sweet potatoes being closely related to Ipomoeas or morning glories, which are very popular flowering plants.
These plants are mostly grown for their large, edible, starchy tubers which are distinctly sweeter than Potatoes. They are a vital food crop in multiple countries due to their high nutritional value, ease of growth, and versatility.
Plant Characteristics
The most prominent part of the Sweet potato plant is the root, which is large and tuberous with a sweet flavor. These tubers can vary in color from orange, yellow, red, pink, purple, beige, and brown.
The flesh of the tubers also ranges in color from white, yellow, pink, red, orange, and purple. The most commonly grown one has orange or pink colored flesh and is sweeter than the one with white or pale yellow flesh.
Sweet potatoes are rich in carbohydrates, fiber, and essential nutrients like potassium, calcium, iron, manganese, etc.
They were eaten as famine foods in olden times since they were cheaper than other alternatives like rice, maize, and wheat. The darker-colored sweet potatoes have more beta-carotene, which is a precursor to Vitamin A.
Sweet potatoes are consumed in most countries of the world in various forms including steamed, baked, grilled, sauteed, fried, mashed, and a hundred other preparations from side dishes to desserts.
The stem of the Sweet potato is a long, sprawling vine that can grow 3-5 meters long, trailing on the ground. It is pale green or sometimes purple in color with roots produced along the nodes where it touches the soil.
The stem is soft with a hollow texture to transport water and nutrients quickly to all parts of the plant.
Leaves of the Sweet potato are typically heart-shaped, but can also be kidney-shaped, rounded, triangular, lobed, or elongated depending on the variety.
Leaves are 10-20 cm long and range in color from green to yellow to purple. Tender leaves and shoots are edible, eaten raw, or cooked like spinach leaves. Sweet potato leaves are rich in Vitamin C, and have a tender texture with mild sweetness.
Sweet potato flowers resemble those of morning glories, since they both belong to the same genus Ipomoea. They are usually solitary or growing in small clusters, and each flower is about 6-8 cm in diameter.
These tubular flowers have merged petals and a darker-colored center that has the stamens. The flowers range in color from white, lavender, pink, and purple.
Flowering happens during spring and summer; the plant grows, flowers, and produces tubers in 4-9 months. Because of their beautiful foliage and flowers, Sweet potatoes are sometimes grown as ornamentals in gardens and parks.
Propagation of Sweet potatoes happens through stem cuttings since the plant does not usually produce fruits or seeds. Although rare, the plant is capable of producing small capsule-like fruits that are 5-8 cm long containing 2-4 seeds. These seeds are very small and not very useful for propagation.
Gardening tips
Sweet potato plants need good sunlight and well-drained, porous soil. Since the tubers are produced underground, waterlogging or clayey soil conditions can prevent the plant from growing and producing sweet potatoes.
Regular watering is needed especially during summer months. Fertilize the soil when you are planting the sweet potatoes and also just before they start flowering and producing tubers.
Spacing the plants 80-100 cm away from each other is important so that they can grow and spread well without competition from other plants.
Sweet potatoes are not climbers like most morning glory plants, but they love to trail on the ground, producing multiple roots where the stem nodes touch the soil. So ensure that the soil is loose, rich, and nutritious.
They are resistant to most pests and rarely need pesticide spraying. Since the stems grow quickly and cover the soil, it prevents the growth of weeds. Since these plants grow and produce tubers very quickly, they can be grown on agricultural land between crops.
Uses of Sweet potatoes
In addition to being rich in fiber and micronutrients, Sweet potatoes have medicinal uses in the treatment of measles, stomach disorders, diabetes, and vitamin deficiencies.
There are innumerable dishes made all over the world using sweet potatoes. They are eaten raw, steamed, or roasted in many parts of Asia.
Sweet potatoes are made into soups, fried and added to sugar syrup to make desserts, candied to make Goguma-mattang or Korean sweet potato, marinated in a batter to make fritters, used as pizza toppings, added to meat dishes to absorb the spicy masalas, made into stir-fries and many many more preparations, all of them very popular in different countries.
Though they are called yams in certain parts of America, they are very different from true Yams. Sweet potatoes are more closely related to Ipomoeas or morning glories which are ornamental garden plants.
Their sprawling vines and fast-growing nature make them excellent ground cover plants to protect the topsoil in slopy areas, and also to prevent weeds from covering the surface.
Sweet potato plants, especially the purple variants are grown as ornamental plants in gardens and landscaped areas. Parts of the plant are used for making dyes.
Sweet potatoes also make good aquarium plants with their roots submerged in the aquarium soil and stems growing out of the water, trailing along the sides.
Propagation
Propagation is through seeds, slips, and stem cuttings.
Since most Sweet potato plants do not bear fruits or seeds, propagation through seeds is very rare. Healthy sweet potatoes placed in water will grow slips or small shoots from the top of the tuber, which can then be separated and planted.
Long stems with roots at the nodes can be separated from the parent plants and replanted as new plants. This is the easiest method of propagation for Sweet potato plants.
Photographed at: Acharya Jagadish Chandra Bose Indian Botanic Garden, Howrah; Koonammavu, Kerala; Bangalore International Center
