How To Grow And Care For Sweet Potato Vines

Sweet potato vines (Ipomoea batatas) are ornamental versions of the sweet potato, grown for their eye-popping foliage instead of tasty tubers. This easy-to-grow plant can add dramatic flair when spilling from pots and hanging baskets or used as a ground cover that sprawls across garden beds and borders. The leaves come in dark shades of black, red, and purple; bright chartreuse shades of lime and yellow greens; and even variegated. They can be three-lobed, heart-shaped, or deeply cut like a Japanese maple leaf.

Sweet potato vine is typically grown as an annual during the warm months, though the tubers (edible but bland or bitter) can be stored for planting the following spring. Plant them after all danger of frost has passed and temperatures have warmed in late spring or summer. As a self-propagating plant and rampant grower that can reach 10 feet in a single growing season, this vine requires occasional pruning to keep it in check.

Plant Attributes

Sweet Potato Vine Care

Sweet potato vines need ample amounts of heat and direct sunlight. The more they get, the better they do. These plants will grow in light shade, but their colors will be duller. Give them moist, fertile, well-drained soil. Fertilizing every two weeks will result in the fastest growth. Some varieties, such as 'Margarita', form large tubers you can dig and save over winter in colder zones, but the others do not. Sweet potato vines will spread rampantly as a ground cover over the course of the summer if not trimmed.

Light

Sweet potato vines thrive best when receiving at least six or eight hours of daily sunlight. Some will grow in partial shade, but the foliage will be richer, more vibrant, and more vigorous when planted in full sun.

Soil

Well-draining soil is essential for sweet potato vines as the tubers are prone to root rot. These plants will tolerate most soil pHs, but slightly acidic to neutral is preferred. Choose an all-purpose potting soil with fertilizer or organic matter if growing in containers. Amend garden soil with compost before planting.

Water

Sweet potato vines should receive at least an inch of water weekly through rainfall or watering. Keep the soil moist but well-draining even though these plants are relatively drought-tolerant once established. Proper watering helps sweet potato vines to produce vibrant foliage and prevents wilting. During the summer or extended periods of heat, water more frequently.

Temperature And Humidity

Like other tropical plants, sweet potato vines thrive in warm, humid climates but don't require high humidity to survive. During prolonged periods of heat, water more frequently so the plant does not dry out.

Wait until the last frost passes before planting sweet potato vine in the spring or early summer. Sweet potato vines require nighttime temperatures above 40°F to prevent damage. Extended periods of lower temperatures, around 55°F, can slow growth. They're winter hardy in USDA Zones 9 to 11, but may die back or look ragged during cold months.

Fertilizer

Use a well-balanced and slow-release fertilizer when planting. For faster growth, add a water-soluble, balanced fertilizer such as 10-10-10 every two weeks. Fertilizer will increase sweet potato vines' naturally vigorous nature.

Types of Sweet Potato Vines

Most sweet potato vines are vigorous growers that can easily conquer other filler companions, so use big containers or cut them back when they get out of hand. Some varieties have more compact growth for a tidier look. Here are some popular sweet potato vine varieties:

• 'Margarita': Bright chartreuse 'Margarita' (also called 'Marguerite') has heart-shaped leaves, and as one of the first sweet potato vines offered, it's become a classic annual spiller in containers. 'Margarita' is highly vigorous and can grow 8 to 10 feet in a single season.
• 'Ace of Spades': 'Ace of Spades' has heart-shaped, purple leaves. It's a little less rampant than 'Margarita,' although 6 feet of growth in one season is still possible.
• 'Goldfinger': 'Goldfinger' has three-lobed, bright chartreuse leaves. Though vigorous, it only spreads 24 to 36 inches.
• Sweet Caroline Raven™: This variety has dark purplish-black foliage with a deep-cut, three-lobed leaf shape. It's bushy and compact, growing only 2 to 4 feet.
• Illusion® Garnet Lace: Garnet Lace has five-lobed leaves in a reddish-purple color with splashes of green. This one spreads 2 to 4 feet.

Pruning

Prune sweet potato vines as necessary throughout the spring, summer, or fall. Remove dead, damaged, or diseased vines with sterilized pruning shears. Use pruning as a way to curtail vines from spreading beyond its boundaries. When grown in direct sunlight and with proper care, sweet potato vines need trimming to avoid overcrowding and potentially overtaking other species. Alternatively, pruning is one way to encourage more vines to emerge. Use garden shears to cut about 1/4 of an inch above a leaf node to stimulate new growth.

Propagating Sweet Potato Vines

Sweet potato vines quickly propagate using cuttings from existing plants. The best time to do this is in spring or summer, or in early autumn if you live in a warm climate. You can plant the cuttings in the garden or overwinter them indoors until the following spring. Some varieties are patented, meaning you are not allowed to propagate the plants. You can root the cuttings directly in soil following these steps:

1. Fill a container with peat moss, perlite, and vermiculite. Water soil mixture.
2. Select the tip of a vine that is 6 to 12 inches long. Using sterilized pruning shears, cut below a leaf node and then use your fingers to remove the leaves from the lower two-thirds of the cutting. 
   
3. Use a pencil or your finger to make holes in the potting soil. Before placing a cutting in each hole, dip the cut end into a rooting hormone to stimulate growth. 
4. Pack the soil around the cuttings and cover the entire container with a clear plastic bag or dome to increase the humidity, making sure the plastic doesn't come into contact with the plant. 
5. Place in bright, indirect light in a warm room while roots emerge. Mist with water to moisten the soil as needed.
6. Give cuttings a very gentle tug after two to three weeks to see if a strong root system is developing. If the plant is well-rooted, gradually introduce the vine to sunlight and cool temperatures before transplanting it outdoors. Alternatively, you can continue growing it in a container as a houseplant until you're ready to transplant in the spring.

You can also root cuttings in water first, following these steps:

1. Select the tip of a vine that is 6 to 12 inches long. Using sterilized pruning shears, cut below a leaf node and then use your fingers to remove the leaves from the lower two-thirds of the cutting. 
2. Place cuttings in a glass of room-temperature water and set in a warm room in bright, indirect light. Replace the water every few days so it stays fresh.
3. Roots should begin to emerge within a week. After roots grow to 3 inches, the cuttings are ready to plant in potting soil. You can plant them outdoors if it's still warm outside (making sure to gradually expose them to increasing amounts of sunlight for a week first), or plant them in a container to keep indoors if it's the end of the growing season.

Some gardeners like to save sweet potato tubers for planting the following spring instead. Follow these steps if you would like to propagate tubers:

1. Dig up the tubers before the plants are exposed to frost. Remove the tubers from the soil and cut off the vines. Brush off the dirt and set them out to dry for 24 hours.
2. Store the tubers in peat in a cardboard box or paper bag. Place the tubers in a slightly cool, dark place over the winter, like in your basement. They survive best when stored in a room that is 55-65° F.
3. Once nighttime temperatures are at least 55° F in spring, you can replant the tubers. (Don't rush this, as sweet potatoes require a soil temperature of around 65°.) Plant 2 to 3 inches deep in rich, well-drained soil.
   

How To Grow Sweet Potato Vines From Seed

Growing sweet potato vines from seed is challenging and rarely done. Garden center varieties either don't bloom or are sterile. Growing from cuttings or tubers is much easier and will allow you to propagate a plant that is identical to the mother plant.

Potting And Repotting Sweet Potato Vines

Pot your sweet potato vine in organically rich, deep, well-draining soil. A good quality potting mix with a little compost mixed in works well. A taller container (or alternatively, a hanging basket) will provide more space for the vines to trail down the sides. Make sure the container has drainage holes so the soil doesn't become overly soggy.

Sweet potato vine is often mixed with other flowers and foliage in summer containers. You can fit three to four plants total in a 10-12 inch container or four to six plants in a 14-16 inch container, with a couple of inches of space between plants. (If you are including flowers that grow large and bushy, use fewer plants.) Place sweet potato vine about an inch from an outer edge so it can easily grow over the side.

Overwintering

Depending on your climate, sweet potato vine tubers can go dormant in frost-free areas, sprouting new vines to replace the dead vines in the spring. If your area experiences temperatures below 40°F, you'll need to pot up sweet potato vine cuttings to keep indoors over winter or store tubers for planting the following spring.

Common Pests & Plant Diseases

The most common problem with sweet potato vines is discovering leaves riddled with holes. Holes can be the handiwork of the sneaky golden tortoise beetle. To control this pest, spray your plants according to label directions with neem oil or spinosad. Depending on your location, other potential pests include aphids, caterpillars, whiteflies, flea beetles, and weevils, which can be handled similarly. Aphids and caterpillars can often be removed by a strong spray of water.

Fungi like verticillium wilt or fusarium can infect the soil surrounding sweet potato vines. These fungal infections, starting with yellowing leaves at the base, spread and cause crown rot or root rot. With fusarium wilt, leaves eventually wilt and brown or black streaks develop inside stems. The best treatment is prevention: provide good drainage, don't overwater, and avoid overcrowding in pots. Dispose of infected plants to prevent spread. Don't replant sweet potato vine in soil that could be contaminated.

Common Problems With Sweet Potato Vines

Sweet potato vines aren't prone to serious problems, but improper care can lead to issues. Here are a few problems that impact sweet potato vines:

Curling Leaves 

Underwatering causes sweet potato vine leaves to curl or wilt. Keep the foliage vibrant by watering deeply every time, making the soil consistently moist but not waterlogged. Also check the undersides of leaves to see if pests like spider mites could be damaging the foliage, and apply neem oil if needed.

Leaves Turning Black

Sweet potato vine leaves can blacken from cold temperatures, pests, or fungal infection. If the weather or pests aren't the cause, your plant is most likely infected and should be disposed of.

Leaves Turning Brown And Yellow

Yellowing or browning leaves are often an indication of overwatering or poor drainage. Improve drainage if possible and reduce watering. Maintain good airflow between the vines and plenty of sun exposure. If the leaves begin to wilt and there are brown or black streaks inside the stems, the plant is infected with fusarium wilt and should be disposed of.

Damage from weed killers can also yellow leaves and stunt growth. Be careful when spraying anywhere near sweet potato vine.