How to Propagate a Sweet Potato Vine

Gardeners prize ornamental sweet potato (Ipomoea batatas) for its vibrantly hued foliage that comes in a wide range of colors and patterns. This herbaceous perennial thrives throughout U.S. Department of Agriculture plant hardiness zones 9 through 11. Although you can buy established ornamental sweet potato plants from nurseries, save money by propagating this vine at home.

If you have access to an established ornamental sweet potato vine, take a cutting and root it in water to start a new plant. This is one of the least labor-intensive options for propagating this ornamental perennial. Wipe down a pair of pruning shears with rubbing alcohol -- this sterilizes the tool to prevent spreading plant diseases -- and snip off the growing tip of the vine. For best results, the cutting should be approximately 12 inches long.

Fill a quart-sized glass or plastic jar with water. Pluck off any leaves on the bottom end of the cutting that will be submerged in water. Place the cutting in the jar and put the jar on a sunny windowsill. Change the water once a day to keep it from stagnating. The vine should grow roots within four weeks. Once roots appear, transplant the rooted cutting into an outdoor garden bed.

Take a 12-inch cutting off the growing tip of an established ornamental sweet potato plant. Pluck off almost all of its leaves except for the leaves on the top couple inches of the cutting. Instead of placing the cutting into a glass of water, bury it an inch deep in a tray of potting soil or soil-less potting mix. The cutting should be buried at an almost horizontal angle so most of it is submerged except for the top couple of inches at its end.

Water the tray once or twice a day or as necessary to keep the soil moist. The cutting should take root within about four weeks, developing roots all along the buried portion of the vine at the bumpy nodes where the leaves once grew.

Slips -- transplants from a sprouted ornamental sweet potato tuber -- are

one of the most common ways this vine is propagated. This method, however, sometimes is not successful and may take several attempts. You'll need a sweet potato tuber, either from a recent potato harvest or from a garden store or nursery. Stick four toothpicks around the middle of the potato and place it into an open-mouth jar so the potato is suspended by the toothpicks resting on the rim.

Add enough water so the bottom half of the tuber is submerged. Change the water once a day. Sprouts will emerge from the tuber. Wait until they're approximately 12 inches long. Twist the sprout at its base to remove it from the mother tuber. This sprout is now ready for transplanting into the garden bed.

Sweet potato vines produce roots at their nodes -- the bumpy point on the vine that also grows leaves -- as they creep along the ground. If you have an established plant, use the ground layering method to start a new one. Identify a portion of the vine that includes a node, and bury this section under an inch or two of soil. After a few weeks, this node will produce roots of its own. Wipe down pruning shears with rubbing alcohol to sterilize them, and trim the part of the potato vine that connects the newly rooted vine with the mother plant. Dig up the newly rooted stem with a garden spade to discover an independent, rooted sweet potato vine.

Ornamental sweet potatoes are very sensitive to cold temperatures. Wait at least three weeks after the last frost date in your region before transplanting young sweet potato plants outside. Choose a location that receives full sun. Prepare the garden bed by breaking up the soil to a depth of 6 to 8 inches and mixing in 3 pounds of 5-10-10 fertilizer for every 100 square feet of garden space. If you have a rooted slip or a vine cutting started in water, take the vine and bury its rooted base approximately 4 inches deep. If you started the vine horizontally in a soil tray, gently remove the vine from its tray and bury it in the prepared garden bed at the same depth you started the vine.