Answer: The ornamental sweet potatos (Ipomoea batatas) are fast growing, twining vines with palmately lobed leaves. These showy forms produce a tuberous root identical in appearance to the common (green leaved) sweet potato but probably not tasty. Late in the season tubular, fairly large flowers appear which are similar to morning glories. Usually they are not particularly noticeable, though, because the foliage claims most of the attention. Three types are of ornamental sweet potato are cultivated for annual, summer vines: 'Blackie' with dark purple, nearly black foliage; 'Margarita' with chartreuse leaves; and 'Tricolor' with pale green, white and pink margined leaves. 'Blackie' and 'Margarita' come back with the same color foliage as the mother plant, but 'Tricolor' may revert to green.
Plant in reasonably good, loose, well drained soil, and water as needed. Once established, the plant is not particularly "thirsty," since the underground tuber retains enough water to get through some dry spells. Cut often if needed to control for size and to create more branching. The vines are vigorous and will put on new growth immediately. Beetles can create annoying holes in the foliage; either tolerate imperfection or spray with insecticide such as pyrethrin or malathion.
Light: Full sun to mostly shade.
Moisture: Average - leaves droop when the vine needs water.
Hardiness: USDA Zones 9 - 11. Grow as an annual in other zones.
Propagation: Where the ground freezes, dig roots in fall and put in dry storage. Otherwise, tubers may be left in the ground or lifted for division in spring. To increase, cut tubers into pieces, making sure that each has at least one "eye" (sprout).
Although sometimes these vining plants are sold as Sweet Potato Vines, look for Ipomoea in your garden center.
Good luck with your planter box!
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