Black sweet potato vine is a favored ornamental plant. Its striking, deeply lobed, dark purple to almost black foliage provides a dramatic visual contrast in garden designs. This plant is appreciated for its vigorous growth and its ability to act as a bold accent.
Growing Black Sweet Potato Vine
Black sweet potato vines thrive in ample sunlight. For optimal growth and rich dark hues, provide at least six hours of direct sun daily. While the plant tolerates some partial shade, especially in hotter climates, too little light can cause the foliage to appear greener and growth to become leggy.
Plant black sweet potato vine in well-draining soil rich in organic matter. An ideal soil pH range is between 6.0 and 7.0, which is slightly acidic to neutral. Space plants about 12 to 18 inches apart to allow for their spreading growth.
Consistent moisture is important, particularly during warm, dry periods. Water thoroughly when the top inch or two of soil feels dry, ensuring the plant receives about one inch of water per week. Overwatering can lead to root rot, so allow the soil to dry slightly between waterings. Fertilize with a balanced liquid fertilizer every two to four weeks during the active growing season to support vigorous growth.
Pruning helps manage the size and shape of black sweet potato vines. Pinching back growing tips encourages bushier, denser foliage. If vines become excessively long or unruly, cut them back to a desired length at any point during the growing season. This promotes fresh new growth and maintains a tidy appearance.
Creative Landscape Uses
The black sweet potato vine is versatile in landscape design. Its trailing habit makes it an excellent “spiller” in container arrangements, cascading gracefully over the edges of pots and hanging baskets. The dark foliage creates a striking visual foundation for brighter flowering annuals or contrasting chartreuse foliage plants.
As a ground cover, its vigorous vines spread and fill garden beds, providing a dense, dark carpet. In mixed borders, it weaves among other plants, adding texture and depth with its deeply lobed leaves. The rich, dark foliage provides a dramatic backdrop, making lighter green or brightly colored plants stand out. Its ability to contrast and complement makes it a valuable asset in dynamic garden compositions.
Understanding Edibility and Safety
While black sweet potato vines are related to edible sweet potatoes, they are cultivated primarily for ornamental foliage. Their tubers are not intended for human consumption, typically having a starchy, unpalatable taste and less desirable texture than common edible varieties.
Consuming parts of ornamental sweet potato vines, including the tubers, may lead to mild digestive upset. The plant’s value lies in its decorative qualities, not as a food source.
Overwintering and Propagation
In regions where temperatures drop below freezing, black sweet potato vines are often treated as annuals, but they can be overwintered indoors. One method is to dig up the entire plant before the first hard frost and pot it. Provide bright, indirect light and reduce watering during cooler months.
Another approach is to store the tubers, similar to dahlias. After the first light frost, cut back the foliage, dig up the tubers, and allow them to dry for a few days. Store them in a cool, dark, dry location, such as a basement, in a container filled with peat moss or sand.
Propagating new black sweet potato vines from cuttings is straightforward. Take 4 to 6-inch stem cuttings, ensuring each has at least two or three nodes. Remove lower leaves and place cuttings in water or a moist potting mix. Roots typically form within a few weeks, allowing for new plants.