Ipomoea batatas

Ipomoea batatas, ornamental sweet potato, has become a popular plant for landscapes, large monoculture containers and combination planters.

Bob Lyons, director of the JC Raulston Arboretum at North Carolina State University in Raleigh, is partial to the Sweet Caroline series developed at North Carolina State. Plants in the series, developed by university breeders Craig Yencho and Ken Pecota, are characterized by short internodes, reduced root size, smaller, deeply serrated leaves and compact, mounded growth habit, which makes them better suited for containers and landscape plantings.

Four patented cultivars, named for their foliage color (Light Green, Red, Bronze and Purple), are propagated by Bodger Botanicals and available through Michell's.

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Stick unrooted or rooted cuttings in a sterile, well-drained growing medium with a pH of 6-6.5. Keep the medium evenly moist to avoid plant stress. Stress will slow plant development and cause flowering. Unrooted cuttings usually take three to four weeks to root.

Because of the compact habit of the Sweet Caroline series, plants can be grown in 4-inch pots without growers having to be concerned with them tangling together or overgrowing the container too quickly.

During propagation, maintain a growing medium temperature of 70F-73F for three to four weeks. After the cuttings are well rooted in the pot, which usually take two weeks, maintain day temperatures of 68F-80F. Night temperatures should be 62F-65F. Once plants are established, finishing day temperatures should be 65F-80F, with night temperatures at 55F-65F for about two weeks.

Light levels should be medium to high (4,500-7,000 footcandles) during production. Plants transplanted into shaded landscape areas perform well, but the foliage color may be less intense than in high-light locations.

Feed plants with 100-200 parts per million nitrogen constant feed using a balanced fertilizer. No growth regulators are required.

Aphids and whitefly are the most common insect problems. Scout for these and control with a preventive program. Botrytis is the most prevalent disease problem and can be controlled with good air movement around plants and a preventive control program.

Like ivy geraniums, ipomoea is susceptible to oedema, which occurs when plant cell walls burst from excessive internal cell pressure caused by high humidity. Rapid and large changes in temperature and humidity promote this physiological disorder. Maintaining stable humidity and temperature levels along with good air movement around the plants will help control this.

Specifics

Name: Ipomoea batatas

Crop timing: From sticking to finished 4-inch plants, unrooted cuttings take eight to nine weeks. When starting with rooted cuttings, plants in 4-inch pots finish in four to five weeks.

Grower benefits: Sweet Caroline series plants have reduced root size and compact habit, which make them better suited for 4-inch pot production. No major pest problems. Can be used as a landscape or container plant in monoculture or combinations.

Selling points: Sweet Caroline series has colorful foliage and its compact, mounding habit enables the plant to be used in multiple ways.

For more: Bodger Botanicals, 1800 Tyler Ave., South El Monte, CA 91733; (626) 442-6161; fax (616) 442-4100; sales@bodger.com; www.bodger.com. Henry F. Michell Co., P.O. Box 60160, King of Prussia, PA 19406-0160; (800) 422-4678; fax (610) 265-4208; bolley@michells.com; www.michells.com/Bodger/bodger.htm.