Although tender to frost, the sweet stevia herb grows well in containers.
Stevia (Stevia rebaudiana) is an herbaceous short lived perennial that reaches about 20-30 in (50-75 cm) in height with a spread of around 18-20 in (45-50 cm). It has opposite leaves that are oblong and have toothed margins. The tiny white flowers appear late in the summer. The leaves and young stems are sweet to the taste and the plant is grown for use as a sugar substitute.
Piqueria trinervia is also called Stevia, but this member of the sunflower family is cultivated for its pretty sprays of little white flowers that are commonly used commercially in floral arrangements.
Location Stevia rebaudiana is native to Paraguay, Bolivia, Argentina and Brazil, where it has been cultivated for centuries by the Native American Guarani. Stevia is grown commercially in many parts of the world and especially in Japan, China, Korea, Malaysia, Thailand, Israel and much of South America, where it and its extracts are used as sweeteners in many applications.
Culture Light: In the warmest climates, stevia does best with some shade; in more temperate regions it likes full sun.
Moisture: Stevia grows well in ordinary garden soils. It is susceptible to root rot, so be sure not to overwater. Stevia plants have fine roots near the soil surface, and a layer of mulch will help keep these from drying out between waterings. Hardiness: USDA Zones 9-11. Stevia rebaudiana is often grown as an annual in the ground, set out after all danger of frost has past. In frost free climates it can be grown as a perennial, but for a single plant, a container that can be brought in before frost is the way to go. There is some evidence that established plants can take a light freeze, dying back in winter and returning in spring. If this turns out to be true, stevia should be listed as hardy in zone 8. Stay tuned.
Propagation: Stevia seeds germinate poorly and propagation is usually done from cuttings. Furthermore, seedlings can vary greatly in sweetness, so cuttings taken from plants of known quality will produce new plants with the same quality of sweetness.
A "sugarleaf" on the way to a glass of (low calorie) iced tea.
Stevia is grown commercially for the glycosides that give it its sweet taste. Stevia extracts are used to sweeten drinks (including soft drinks), other food products, and are used as a table sweetener in many countries.
Native South Americans used stevia medicinally to treat a variety of ailments. More recently, studies on extracts from the stevia leaf have suggested possible benefits in treating obesity, hypertension, and osteoporosis. Stevia is a useful sweetener for diabetics and others who need to restrict carbohydrate intake.
Grow stevia in pots or in the vegetable garden. Concentrations of the sweetening chemicals increase with shorter days and cooler temperatures, so pick the leaves in autumn before the first frost. When the plant flowers, leaf production declines, so to get the biggest harvest of leaves, nip off flower buds as soon as they appear. The fresh leaves should be dried and then ground for use as a sugar substitute. Ground stevia leaves can be added to drinks or foods to provide sweetness without any food value. A tablespoonful (15 ml) of dried, ground Stevia sweetens as much as one cup (236 ml) of sugar.
What makes stevia taste sweet are a couple glycosides that have been named stevioside and rebaudioside. (How clever to come up with these names!) These chemicals are reportedly up to 300 times sweeter than ordinary table sugar, sucrose. The leaves of the Stevia plant contain about 12% of these chemicals and are said to have as much as 40 times the sweetening action of sucrose. And this with virtually no calories, no carbohydrates, and a glycemic index of zero. Nor are the glycosides susceptible to fermentation as is sugar. They just TASTE sweet.
In the U.S., stevia has been variously relegated and regulated as a food additive (sweetener) or a dietary supplement, and has even been banned from time to time, some say because of political influence from makers of artificial sweeteners. Today stevia extracts are available commercially, and most often used to sweeten tea and coffee.