How to Grow and Care for Sweet Potato Vine

Sweet potato vine (Ipomoea batatas) is a fast-growing annual and classic "spiller" plant commonly used for container gardening thanks to its long tendrils of varied leaf colors that include purple and burgundy and shapes that spill over the edges of pots. Typically grown as an annual but as a perennial in warmer regions, its vines are cultivars of the same species as edible sweet potatoes but are only ornamental as they are very bitter.

Sweet potato vine grows well in tropical and humid conditions with sun or some shade, prefers soil on the acidic side, and is best planted in the spring when temperatures stay consistently above 50 degrees Fahrenheit. It thrives in weather that hovers around 75 degrees Fahrenheit. 

Sweet Potato Vine Care

Here are the main care requirements for growing sweet potato vine:

• Plant in sun or partial shade.
• Use rich, well-drained soil.
• Water frequently without letting the plant become waterlogged.
• Frequently trim sweet potato vine to help keep this vigorous grower in check. Use the parts you trim back can be used to propagate the plant elsewhere.

Light

Sweet potato vines love the sun but will also grow in partial shade and sometimes full shade. The more sun the plant gets, the more vibrant its leaf color will typically be.

Soil

These plants prefer moist, well-drained soil that's nutritionally enhanced with organic matter. They are prone to root rot if their soil remains too wet. Make sure that the container you choose has ample holes for drainage.

Water

Sweet potato vines are drought-tolerant, though they will grow more vigorously with frequent watering. Water enough to keep the soil consistently moist but not overly wet. Its leaves will wilt when the plant is thirsty.

Temperature and Humidity

These vines like the sun more than high heat. In hot climates, they will benefit from some shade, and they should be watched carefully, so their soil doesn't dry out. They thrive in many humid climates but don't need high humidity as other tropical plants do.

The plant grows best at an average temperature of 75 degrees Fahrenheit and does not tolerate frost. It prefers sunny days and warm nights.

Fertilizer

Fertilize sweet potato vines if you want them to grow vigorously. A weekly feeding with a well-balanced fertilizer during their growing season will boost growth, but given their naturally robust habit, you may find that feeding also increases the need to cut them back.

Types of Sweet Potato Vine

• Ipomoea batatas ‘Sweet Caroline’: Popular as a ground cover, this varietal is available in five different colors, including light green, yellow-green, bronze, purple, and red with maple-shaped leaves.
• Ipomoea batatas ‘Blackie’: It has dark purple, maple-like leaves and sometimes flowers with purple, trumpet-shaped blooms.
• Ipomoea batatas 'Ragtime': This is one of the varieties with narrow, divided leaves; its coloring is a pale purple with some attractive natural variation.
• Ipomoea batatas 'Ace of Spades': This plant has long trailing foliage and is tolerant of heat. It derives its common name from it's heart-shaped leaves.
  
• Ipomoea batatas 'Goldfinger': A hardy plant with good heat tolerance, this type does well in containers with foliage that can trail over the sides.
• Ipomoea batatas 'Midnight Lace': A tuberous perennial, this makes for a wonderful hanging basket or window box plant. It has deeply dissected dark purple palmate leaves laced with magenta.

Pruning

Prune sweet potato vine to remove broken or sickly vines. Cut back rapidly spreading vine tips that have exceeded their boundaries to prevent them from extending too far. Cut about 1/4 inch above leaf nodes to encourage new growth. Use bleach or rubbing alcohol to sterilize a pair of pruning shears between the pruning of different plants. The more the vine is pruned, the more it will try to regrow.

Propagating Sweet Potato Vines

Sweet potato vines are easy to grow from existing plants. Cutting is the best way to propagate, but you can also plant the tubers in the spring.

To propagate with cuttings:

1. If you live in a place that gets wintery weather, you'll want to take a cutting from your outdoor sweet potato vines in the autumn before the first frost. The plant dies off when exposed to frost. You'll need pruning shears or snips, a jar of water, and a sunny spot.
2. Using clean, sharp garden pruning shears, cut off a branch that has several leaf nodes. Remove the leaves off of the bottom few inches.
3. Submerge the stem in water. In a few days, the plant will grow roots. 
4. Keep the water level constant. Refill the jar with clean water every week to discourage bacterial growth. The plant can live indoors in water in a sunny spot throughout the winter.
5. Replant it in the garden in moist, well-draining soil in a sunny spot outdoors. Harden off the plant before placing it in the garden to acclimate it to outdoor conditions.

To propagate using its tubers:

1. Save the tuberous roots for the next season. You'll need a box, peat, or vermiculite, and a cool, dry place, such as a basement, crawlspace, or root cellar.
2. Dig up the tubers before the first frost, and let them dry. Bury them in peat or vermiculite. Do not let them touch.
3. Inspect the sprouted tuber for signs of disease or infection in spring. Cut off and discard any blackish areas, visible wounds, puckered spots, or discoloration with a non-serrated, clean knife.
4. Divide the tuber using the sterile knife, making sure each tuber has at least one eye and some shoots or roots.
5. Plant them after the last frost in moist, well-draining soil, 2 inches deep at least 2 feet apart in a sunny spot.

To propagate in water:

1. Drop the sweet potato in a container of water with the third top of it exposed to the air.
2. Keep the container in a spot that receives plenty of bright sunlight.
3. Fertilize monthly.
4. Cut back the vine if it becomes too leggy to promote fullness.
5. Wait about 2 weeks for the sweet potato to bud and watch the vines grow from there for the next few months.

How to Grow Sweet Potato Vine From Seed

Sweet potato vines are rarely grown from seeds, since they can grow from cuttings and their tuberous roots. Also, since it doesn't flower reliably, you can't always get seeds. Many varieties are sterile. If you'd still like to try to grow the plant from seeds, take these steps:

1. Presoak seeds for 12 hours in warm water to help with germination.
2. Fill a seed-starting tray with a light, soil-less starting mix. Sprinkle the seeds over the tray, spacing them 3 inches apart. Cover them with a light dusting of starting mix.
3. Spray the mix with water from a spray bottle and cover the tray with plastic wrap or a humidity dome.
4. Store the tray in a warm place. Keep the starting mix evenly moist
5. Once you see seedlings, remove the plastic wrap and move it to a sunny window or under a grow light.
6. Sweet potato vines dislike root disturbance, so transplant immediately after sprouting or grow in biodegradable pots.
7. Harden off seedlings before transplanting them in the ground or outdoor container.

Potting and Repotting Sweet Potato Vine

For sweet potato vine, choose a taller pot or basket (hanging or otherwise) of any material so the vines have ample room to spill and trail over the edge of the container. Make sure your container or window box has ample drainage holes. Fill the pot with good-quality potting soil mixed with compost. Water the container once a week until the water begins leaking from the drainage holes. Plants will thrive if the container is kept in full sun rather than shade.

Overwintering

Cutting is a good way to overwinter sweet potato vines because they will last all winter in the water and be ready to plant in the spring. Another way to overwinter sweet potato vine is to dig up the sweet potato vine's tuberous roots and store them in a cool, dry space in peat or vermiculite. Come spring, you can plant the sprouting tuber.

Common Pests and Plant Diseases

The golden tortoise beetle likes to feast on sweet potato vines. The insect looks like a teardrop of molten gold. While interesting to look at, the beetle will munch holes in the leaves, making them look like Swiss cheese. Aphids also favor sweet potato vines.

Depending on where you live, other common pests include the sweet potato looper, a caterpillar that chews on the leaves; the sweet potato whitefly, which can drain the plant of nutrients and stunt its growth; and sweet potato weevils can cause yellowing of the vines.

Rotate the planting location of sweet potato vines every season to avoid leaf fungus. The most common fungi are verticillium or fusarium, which can cause yellowing at the base of the plant.

Planting sweet potato vine with ample space to spread and allow air circulation will help prevent disease. If soil pH, nutrition, sun exposure, and water needs are met, it can fight off disease more readily if it occurs.

How to Get a Sweet Potato Vine to Bloom

Bloom Months

Sweet potato vines rarely flower when the daylight is longer than 11 hours, which normally occurs outside the tropics. However, if you do find blooms, you'll see them in the spring or summer.

What Do Sweet Potato Vine Flowers Look and Smell Like?

Sweet potato vines rarely bloom, but when they do, they're glorious. And, they look like purple or pink trumpeting morning glories. The plant is better known for its foliage which comes in various colors including purples, greens, and bronze. The plant does not have a scent.

How To Encourage More Blooms

Sweet potato vines need perfect conditions in the spring or summer months to flower, and that often means sufficient water—moist but not waterlogged—ample sun and a good nutritional balance.

For optimal flowering, use a low-nitrogen, bloom-enhancing fertilizer with a 7-9-5 ratio. Alternatively, a balanced fertilizer may also be used. Pluck off spent flowers to encourage more flower growth if they flower at all.

Common Problems With Sweet Potato Vine

Sweet potato vine is prone to pests and diseases that are often the cause of browning or blackening of leaves, wilting, and ultimately, death. Here are signs to look for and what they may mean:

Leaves Turning Yellow or Brown

Root rot and fungal infection may cause sweet potato vines to develop yellow or brown leaves that wither and drop. Be careful not to overwater as this is the most common cause of infection.

Plant in containers with drainage holes and keep the soil evenly moist but not waterlogged. Pull any infected plants to prevent the spread to neighbors. Plant in a different location to prevent fungal infection from reoccurring the next year.

Blackened Leaves

Sweet potato vines are frost-sensitive. Blackened or mushy leaves can indicate that the plant has frostbite. Pull it up and discard it.

Leaves Wilting or Curling

Keep its soil consistently moist. When watering sweet potato vine, water the soil to a depth of 6 inches. Sweet potato vines will wilt or curl their leaves when lacking water.

Holes in Leaves

Holes in leaves are the sign of an insect feasting on your sweet potato vine, likely tortoise or flea beetles. To get rid of beetles, shake them off into a bucket of soapy water. Spread diatomaceous earth around the plant. You can also apply neem oil to the affected area. Use a plant-based pyrethrin insecticide but only as a last resort since it will also kill beneficial insects.