Sweet potato vines are popular ornamental plants, valued for their vibrant foliage in garden beds and containers. A common question is about their longevity: whether these plants return year after year. The answer depends on the specific climate and the care provided.
Sweet Potato Vine Lifespan and Climate
Sweet potato vines (Ipomoea batatas) are tender perennials. In their native tropical and subtropical regions (USDA Plant Hardiness Zones 9 through 11), they can persist for multiple years as temperatures rarely drop to freezing.
In these warmer zones, the plant’s underground tubers survive mild winters and resprout in spring. However, in colder climates (USDA Zones 8 and below), sweet potato vines are cultivated as annuals. Their tubers and foliage are susceptible to damage from freezing temperatures. Without protection, the plants will not return after a cold winter.
Methods for Overwintering Sweet Potato Vines
For gardeners in colder regions who wish to enjoy their sweet potato vines for more than one season, there are effective methods to overwinter them. Two primary approaches involve either bringing the entire plant indoors or carefully storing its tubers.
Overwintering Whole Plants
One strategy is to transition the whole sweet potato vine into an indoor houseplant. Before the first hard frost, select a healthy plant, inspecting it for pests and treating them with horticultural soap if needed to prevent introducing unwanted insects.
Prune the vines back to a manageable size, leaving about 6 inches of foliage. Repot the plant into a container with fresh potting soil, ensuring adequate drainage, and place it in a location with bright, indirect light, such as a sunny window. During winter, reduce watering, allowing the top inch or two of soil to dry between waterings, and ensure good air circulation.
Storing Tubers
Alternatively, gardeners can store the plant’s tubers. These underground structures contain the plant’s stored energy. Before freezing temperatures arrive, carefully dig up the tubers, avoiding bruising or damage.
After removing the tubers from the soil, gently brush off excess dirt and allow them to cure or dry in a warm, dark, and dry place for a few days. Once cured, pack the tubers in peat moss, vermiculite, or sand within a cardboard box, ensuring they do not touch. Store the box in a cool, dark, dry location above freezing, ideally between 50 and 60 degrees Fahrenheit. Periodically check the stored tubers for any signs of rot or shriveling, removing any affected ones to prevent spread.
Replanting and Care After Overwintering
Once spring arrives and the danger of frost has passed, prepare your overwintered sweet potato vines for their return outdoors. This transition requires a gradual approach to help the plants re-acclimate to outdoor conditions.
Replanting Whole Plants
For whole plants that were brought indoors, slowly reintroduce them to brighter light over a period of about two weeks. Begin by placing them in a shaded outdoor spot, gradually increasing their exposure to sunlight each day. As the plant adjusts, increase watering frequency and consider repotting it into a larger container or its final outdoor location if it has outgrown its winter pot. Initial fertilization with a balanced liquid feed can help encourage new growth.
Replanting Tubers
If you stored tubers, you can begin sprouting them indoors a few weeks before the last expected frost. Place the tubers in a shallow tray of moist potting mix or suspend them partially in water, ensuring a portion of the tuber remains exposed to air. Once sprouts (slips) develop and reach a few inches, detach them from the tuber. These slips can then be planted directly outdoors after all risk of frost has passed, or rooted in water before planting. When planting outdoors, choose a sunny location with well-draining soil and provide initial watering to help establish the newly planted slips or whole plants.