Allen D. Owings
Ornamental sweet potatoes have gained considerable interest among landscape industry professionals and home gardeners over the past 10 years. Varieties include plants that are chartreuse-lime green (Margarita), blackish purple (Blackie) and tricolored (Pink Frost). Other older varieties in the trade include Lady Fingers (with deep lobes and green foliage), Black Beauty and Ace of Spades (both heart-shaped, blackish foliage plants).
New ornamental sweet potatoes have various leaf shapes and growth habits in addition to new foliage colors. These sweet potatoes have been selected for shorter stem lengths between the leaves and reduced root size. They are more compact than most other ornamental sweet potato varieties.
Some of the new sweet potatoes are more conducive to trellising and container plantings when compared with older varieties. Some of these new varieties may produce significant flowering in the landscape during the summer through fall, while others seldom flower.
The most widely available line of ornamental sweet potatoes for home gardeners and commercial landscapers is the Sweet Caroline group, originally developed by researchers at North Carolina State University in 2002. The Sweet Caroline series is readily available in Louisiana with green-yellow, red, light green, bronze and purple foliage. The Sweet Caroline Sweetheart series (with heart-shaped leaves) is available in light green, red and purple while the stand-alone Bewitched variety has maple-leaf-shaped purplish-black foliage. The best foliage colors come when plants are in full sun. There will be less colorful foliage in a shaded or partially shaded planting. Even more new varieties will be available soon.
New ornamental sweet potato series for 2009 include Sidekick from Syngenta Flowers. This series is available in black, black heart and lime colors. The plants are being evaluated in landscape trials at the LSU AgCenter’s Hammond Research Station. The lime-colored variety is lighter in color than the chartreuse-lime green foliage of Margarita, and the growth habit is low-growing and less spreading.
New Desana ornamental sweet potatoes are available from Suntory Flowers in lime, maple, compact red and bronze colors. Lime is the most compact and will not overgrow other plants in landscape beds. The compact red is less vigorous than the Sweet Caroline red-foliaged varieties, and the new foliage opens in shades of red that evolve to green with maroon veins as the leaves mature.
Chillin and Illusion are two new ornamental sweet potato series from EuroAmerican Propagators/Proven Winners. Chillin colors come in limeade, blackberry star and blackberry heart, while Illusion has some of the finest textured foliage in ornamental sweet potatoes and is available in varieties called Emerald Lace and Midnight Lace.
The LSU AgCenter has seven newly developed ornamental sweet potatoes being considered for future release. These new plants originated from the AgCenter’s sweet potato breeding program. These lines were planted at the Hammond Research Station in May 2009 for landscape evaluation/observation studies.
The sweet potato weevil quarantine has resulted in regulation of where ornamental sweet potatoes can be grown and transported. In Louisiana, distribution of ornamental sweet potatoes into sweet potato weevil-free areas is regulated by the Louisiana Department of Agriculture and Forestry. The sweet potato weevil-free parishes are Claiborne, Lincoln, Jackson, Union, Winn, Ouachita, Caldwell, LaSalle, Morehouse, Richland, Franklin, Catahoula, West Carroll, East Carroll, Madison, Tensas and Concordia. These parishes are contiguous and are located in the northeastern portion of the state. Ornamental sweet potato plants originating from or grown in a sweet potato weevil-infested area may not be shipped to sweet potato weevil-free areas in Louisiana or to sweet potato weevil-free areas of other states.
Allen D. Owings, Professor, LSU AgCenter, Hammond Research Station, Hammond, La.
(This article was published in the spring 2009 issue of Louisiana Agriculture.)