The purple sweet potato vine (Ipomoea batatas) is a perennial growing vine in frost-free regions, (USDA zones 9 to 11) and an annual vine in other zones. It is a vigorous growing vine that can be grown in containers or in the ground for an attractive ground cover. Purple sweet potato vine is revered for its unusual dark-purple to nearly-black foliage, which has given this variety of sweet potato vine the name of "Blackie."
Growing a Sweet Potato Vine in the Ground
Turn the soil over in the planting area to 6 to 8 inches deep. Incorporate into the soil a 2- or 3-inch layer of organic media, such as leaf compost, aged manure or peat moss. Remove any rocks, large clods or weeds from the planting area.
Dig a 1-1/2- to 2-inch deep hole in the planting area for each of the purple sweet potato vine tubers. Space each of the planting holes approximately 18 to 24 inches apart if you are planting more than one tuber.
Place a tuber into the previously created hole. Scoop in garden soil and natural material mixture to cover the tuber with approximately 1-1/2 to 2 inches of soil. Tamp the soil down gently.
Water the purple sweet potato vine tuber thoroughly. Keep the soil moist, but never let it become soggy. The tuber should begin sprouting in approximately 10 days to three weeks, depending on growing conditions.
Fertilize the tuber two weeks after planting with a 15-16-17 balanced fertilizer. Follow the manufacturer's instructions for dosage.
Growing Purple Sweet Potato Vine in a Container
Fill the growing container to about 1/2 full with a high-quality potting mix.
Remove the vine from its growing container. Turn the vine upside down and grasp it at the top of the root ball. Strike upwards along the rim of the pot using a sturdy object to loosen the root ball from the container.
Loosen any tangled or matted roots and set the vine into its new growing container.
Pour potting mix around the root system, making sure that the vine will be growing at the same level it was in its previous growing container.
Apply enough water to the container to settle the potting mix, then top off the container with more potting mix. Water the purple sweet potato vine tuber thoroughly.
Place the container in full sun to partial shade.