Herb To Know: Stevia
Nature's calorie-free sweetener.
December/January 2009
By Suzanne Hall
 |
Steven Foster
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Genus: Stevia rebaudiana
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• Also known as sweetleaf and Paraguayan sweet herb
• Hardy to Zone 8
The Guarani Indians of Paraguay and Brazil had been sweetening their bitter beverages with kaa he-he (meaning sweet herb) for centuries before Italian botanist Moises Santiago Bertoni “discovered” the herb in 1887 and recognized it as a previously “unknown” variety of stevia. He named it Stevia rebaudiana in honor of the Paraguayan chemist named Rebaudi, who first extracted the component stevioside, the sweet molecule in the plant’s leaves.
A member of the Asteraceae family, which includes sunflowers and chrysanthemums, the genus Stevia includes nearly 300 species. Of these, only S. rebaudiana is noted for its sweetening power. And sweet it is. Fresh stevia leaves generally have a slight licorice flavor and are many times sweeter than sugar. When dried, stevia leaves are sweeter still. Stevia extract is as much as 300 times sweeter than sugar.
Natural and calorie-free, stevia does not appear to increase blood glucose levels, making it a plus not only for dieters, but also for diabetics. The herb is not, however, without controversy. Although widely consumed in its natural state or as an addition to commercially prepared foods and beverages throughout much of the world (including South America, Japan and other Asian countries), stevia is banned as a food additive in Canada, the European Union and the United States, where the Food and Drug Administration believes the herb has not been thoroughly tested. Because of a wrinkle in regulatory power, though, it may be sold in the United States as a dietary supplement.
It’s easy to grow your own stevia for personal use. In the garden, stevia grows 18 to 30 inches tall with gray-green oval leaves and, periodically, small white flowers. Although many references rate stevia as hardy only to Zone 11, some Zone 9 and 10 gardeners report the plant has survived winters there. Some gardeners in Zone 8 report stevia dies back to the ground in winter, but will grow back in spring. In Zones 7 and colder, you will need to grow stevia as a garden annual or in a pot, which you could move indoors for winter. Set plants outdoors after all danger of frost has passed. Stevia prefers plenty of sunshine and a sandy or loamy soil kept moist, not wet, with mulch or compost. Avoid overwatering potted plants.