What Is The Sweet Potato Plant And Why’s It Popular In The Tropics?

Sweet potatoes (Ipomoea batatas) may look a lot like the regular potatoes we eat every day, but they’re not related. Unlike potatoes (Solanum tuberosum), which belong to the nightshade family, sweet potato is a member of the morning glory family, Convolvulaceae. It’s a root vegetable that we grow for its starchy, sweet storage roots.

Most people confuse it with yams, but there’s no relation there either. The sweet, starchy veggies might be hard to distinguish from their taste and looks, but they belong to entirely different families!

But, if it’s not yam, and it’s not potato either, then the question is, what is the sweet potato plant? How can you recognize it, and what kinds of conditions does it need to thrive? This post will tell you all about this unique root vegetable.

Common NameSweet Potato
Botanical NameIpomoea Batatas
Plant TypePerennial But Is Grown As An Annual
Size (Fully Grown)Height 12 – 15 Inches (30 – 38 cm), Spread 4 – 8 Feet (1,21 – 2,44 Meters)
Sun ExposureFull Sun But Tolerates Partial Shade
Soil TypePreferably A Sandy Loam Soil That Drains Well
Soil pH5 To 6,5
Flower ColorFrom Light Blue To Purple
U.S. Hardiness Zones8, 9, 10, And 11
Native AreaTropical America

Different Sweet Potato Varieties

Even though the plant is native to tropical American regions, sweet potato is grown in many parts of the world, including China, Japan, Hawaii, New Zealand, Australia, and Europe. Due to the plants spread across the globe, there are many different varieties of this root vegetable.

Since the mid-1900s, orange-fleshed sweet potatoes began being marketed by the name “yams” to distinguish them from the usual pale-fleshed varieties. But, these are still varieties of the vegetable Ipomoea batatas, rather than “true yams,” that belong to the Dioscoreaceae family.

Here are the most common varieties you’ll find in the category:

  1. Orlis
  2. Jewel
  3. Darby
  4. Carver
  5. Stokes
  6. Nugget
  7. Apache
  8. Kandee
  9. Vardaman
  10. Gold Rush
  11. Centennial
  12. Red Nancy
  13. Beauregard
  14. Bunch Porto Rico

There are also cultivars from the same species that are bred for their ornamental vines. Though the sweet potatoes from these ornamental vines are also edible, they might not be as tasty. Here are some ornamental sweet potato vine cultivars:

  1. Blackie
  2. Lady Fingers
  3. Bronze Beauty
  4. Sweet Caroline Red
  5. Sweet Caroline Purple

Origins And History Of The Sweet Potatoes

Sweet potatoes are native to tropical Americas and have been cultivated there for at least 5000 years, and the plant was initially called batatas by the natives. The species quickly spread to the Caribbean and southeast America, and from South America, sweet potatoes spread westwards.

It’s been reported that the plant was grown in Cook’s Island since 1000AD. Early Polynesians, who traveled to South America, brought back vine cuttings, introducing the vegetable across Polynesia, Hawaii, and New Zealand.

By the time Columbus reached the “New World,” sweet potatoes were already being cultivated as a major food crop in South and Central America. After that, he introduced the cultivar to Spain somewhere in the 1500s. Several different varieties were being grown in Spain by the late 1600s. From Spain, sweet potato spread to other parts of Europe, though its popularity was slower in northern Europe since the plant prefers warmer climates.

Sweet potatoes were initially called “patata” in Spanish and potato in English, making it difficult to distinguish it from the white (Irish) potato in historical records. The well-known English botanist John Gerard also mentions “potato” in his book Herball, published in 1597. After introducing Irish potatoes (that were also native to South America), American colonists started using the word “sweet potatoes” to distinguish it from the other cultivar.

Today it’s a popular staple of the warmer climates. Currently, China produces almost 95% of the world’s sweet potatoes. Uganda, Spain, Indonesia, Vietnam, and Nigeria are also chief producers, following China.

How To Recognize A Sweet Potato Plant?

Sweet potato is usually grown from the vine’s stem cuttings, which gradually produce new roots and grow into a plant.

The trailing stems of a sweet potato vine spread horizontally, growing 4 to 8 feet long (about 1,21 to 2,44 meters) with dark green leaves and violet flowers. Roots are the main attraction of the plants since that’s where the storage roots develop. After all, that’s where each plant produces 4 to 10 storage roots that take about four months to mature.

Leaves

The leaves vary in color, shape, and size according to the specific sweet potato plant’s variety. In general, they’re heart-shaped, dark green with a broad petiole and purple markings.

Flower

We rarely see any flowers in temperate regions. They’re produced in clusters, funnel-shaped, and their color is either violet, reddish, or white.

Roots

The fibrous roots growing beneath the soil surface grow enlarged structures at the base called storage roots. The storage roots are the ones we harvest for consumption. They vary in shape, size, color, and weight according to the variety, and the skin color ranges from cream, yellowish-orange, pink to dark purple. On the other hand, the starchy flesh can be purple, yellow, orange, or cream.

That SWEET SWEET Potato
© Serjik Ahkhundov – stock.adobe.com

What Climate Does Sweet Potato Thrive In?

People grow sweet potatoes in many regions but remember that they need 3 to 5 months of warm growing days. Other than a warm climate, they don’t demand much extra care.

They’re heat and drought-tolerant and have very few diseases and pest problems that affect them. Anyway, here are few notes to grow the crop in a home garden for a successful harvest.

The Temperature

Sweet potatoes are usually planted from slips (vine cuttings) 3 to 4 weeks after the last expected spring frost date. The soil temperature should be above 60°F (about 15°C) when you plan on planting them in your garden.

Sweet potatoes grow best when the air temperature lies in the 75°F to 95°F (23,8 to 35°C) range, and the soil temperature is somewhere between 60°F to 85°F (15,5 to 30°C).

The Climate

Sweet potatoes like to grow in a warm, sunny spot. So, if you’re living in colder climates, the northern U.S. or Canada, for example, you might want to cover the ground with fabric mulch about three weeks before planting to warm up the soil.

Sweet potato prefers light, loamy, well-draining, or sandy soil, amended with well-aged compost. So, if you have clayey or rocky soil, you’ll get fewer, distorted storage roots. A good thing to remember is that raised beds are an option if your garden’s soil type isn’t ideal for growing sweet potatoes.

Keeping your sweet potatoes well-watered, especially in hot summers, and reducing the watering frequency near the end of the season is a great way to prevent the skin from cracking.

Is It Safe To Eat / Consume Sweet Potatoes?

Sweet potatoes are a plant that is packed with vitamins, particularly Vitamin A, B5, B6, and C. Also, since they offer lower calories than the regular potatoes, they can be a good alternative for those on a diet, but remember that they include sugar.

While they provide many nutritional benefits, it’s essential to know if their consumption is safe for everyone. Are there any drawbacks to eating sweet potatoes? Let’s find out.

Pregnant And Breastfeeding Women

Sweet potatoes are safe for consumption if you’re pregnant or breastfeeding. They’re an excellent source of Vitamin A, which is vital for the growth and development of a new life. But bear in mind that excess consumption isn’t advisable, especially during pregnancy.

Children

They’re nutritious vegetables to offer children from an early age. For example, vitamin A helps with your child’s developmental stages. They’re naturally appealing to kids because of the sweetness and their bright color.

I want to remind you that some babies may be allergic to the vegetable, causing bloating, stomach gas, diarrhea, or vomiting.

People With Allergies

Allergic reactions may occur in specific hypersensitive individuals. Sneezing, nausea, skin rash, itching, and tongue inflammation are common symptoms of handling or consuming sweet potatoes. Minor over-the-counter medication is usually enough to relive the symptoms. In the case of severe reactions, consult a doctor.

People With Diabetes

As we already know, people with diabetes should be concerned about their blood sugar levels and keeping their weight in check. If you want to eat sweet potatoes, eat them in moderation because they are high in carbohydrates, and one cup of sweet potatoes contains about six grams of sugar.

I do want to remind you that it’s always a better choice to cook a healthy meal with sweet potatoes than eating fast food, for example. Why? Well. Mostly because generally fast foods are almost always high in sugar, fat, and salt: NOT GOOD!

To know more about foods that are good but also bad for people with diabetes, check out this article on WebMD.

Medical Conditions

If you have a history of kidney stones, avoid consuming sweet potatoes since the plant has high dietary oxalates concentrations. Excess oxalates may cause the development of calcium-oxalate kidney stones.

People with heart diseases and taking beta-blocker medications should also avoid sweet potatoes.

Pets

Although sweet potatoes are not toxic on their own, the vines are highly toxic to pets. Ingestion of the foliage or any part of the vine can adversely affect your pet’s kidney, heart, brain, and liver.

It’s fair to call this condition sweet potato vine poisoning. It can cause diarrhea, seizure, vomiting, hallucination, drooling, low blood pressure, nausea, liver, or even kidney damage. Your pet will need immediate medical attention if they experience any of these symptoms after eating sweet potatoes.

Featured image credit – © kariphoto – stock.adobe.com

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