Stevia rebaudiana

Stevia rebaudiana is a plant species in the genus Stevia of the family Asteraceae. It is commonly known as candyleaf, sweetleaf or sugarleaf. It is a small seasonal plant which grows to a height of 30–60 centimetres (1–2 feet). It has elongated leaves that grow along the stems and are lined up against each other. The flowers are typically trimmed to improve the taste of the leaves. Stevia is a tender perennial native to parts of Brazil and Paraguay having humid, wet environments. Stevia is widely grown for its leaves, from which extracts can be manufactured as sweetener products known generically as stevia and sold under various trade names. The chemical compounds that produce its sweetness are various steviol glycosides (mainly stevioside and rebaudioside), which have 200–300 times the sweetness of sugar. Stevia leaves contain 9.1% stevioside and 3.8% rebaudioside A.

Description

A perennial shrub. It grows to 0.5-1 m tall. Plants are clumpy bushes about 75 cm high and 60 cm wide. The leaves are 2-3 cm long. They are small, oblong and have teeth around the edge. The flower heads are on the tips of stems. They are in clusters and are white. The fruit are very small and have one seed. They have feathery plumes which help them spread.

Edible Uses

The leaves have a very sweet, liquorice-like flavour and can be eaten raw, cooked as a vegetable, or chewed by those wishing to reduce their sugar intake. They contain 'stevioside', a substance approximately 300 times sweeter than sucrose, though other reports cite the active compound as 'estevin', which is 150 times sweeter than sugar by weight. Dried leaves can be ground and used as a sweetener or soaked in water, with the resulting liquid used in making preserves. Powdered leaves are also added to herb teas.

Traditional Uses

The leaves are dried and can be used for sweetening. They are also used to make a tea. They can also be cooked and eaten as a vegetable. The powdered herb is used as a sugar substitute.

Medicinal Uses

Hypoglycaemic properties are noted.

Known Hazards

May cause dizziness, headache, flatulence, nausea & muscle pain. Caution with diabetic patients. May increase blood pressure lowering effects of allopathic medicine.

Distribution

A tropical and subtropical plant. It is frost tender. It requires a warm and sunny location. It can grow on a range of soils and suits sandy soils. It grows naturally on infertile, sandy acid soils. They do best in rich loamy soil. Composting or mulching is needed on sandy soils. They cannot stand water-logging but need constant soil moisture. Soil temperatures above 10-15°C are needed for satisfactory plant growth. It grows naturally in semi-humid subtropical climates with temperatures between 21°-43°C. It grows where average temperatures are 24°C. It often grows in places with shallow water tables. It requires short day-lengths. It grows in areas with up to 1375 mm of rain a year.

Where It Grows

Andorra, Asia, Australia, Brazil*, Canada, China, Georgia, India, Indochina, Israel, Mediterranean, Middle East, North America, Paraguay*, SE Asia, South America, Tasmania, Thailand, Uruguay, Uzbekistan,

Cultivation

The seed are only sown shallowly. Seeds are slow and difficult to get to germinate. It can be grown from cuttings. It is best to select cuttings from known sweet (high stevioside) plants. Plants should be spaced 40-50 cm apart. Harvesting is done by pruning off the branches then removing the leaves. The plants can be grown for 2 years then are best replanted.

Propagation

Sow seed in spring in a warm greenhouse, barely covering the seed, and ensure the compost does not dry out. Prick seedlings out into individual pots and grow on quickly, planting out after the last expected frosts. Some protection such as a cloche or cold frame for a few weeks after planting out is worthwhile until plants are establishing well.

Other Uses

None known

Production

Sweetness increases with longer growing periods and as temperatures and daylength decrease moving the plant towards a flowering state. The plant is dried and threshed to remove the stem material which has little sweetener content. Leaves can be sold in this condition or are further processed.

Other Information

A potentially useful plant that has been restriced by law in the USA because it competes with nutrasweet! It is widely used in Japan. It is cultivated.

Notes

There are about 235 Stevia species in the neotropics. It is a sweetener much more effective than sucrose. It reduces blood sugar and contains few calories. It is therefore used as a medicine for diabetes and to lower blood pressure. It has antioxidants.

Synonyms

Also Known As

Candyleaf, Caa-ehe

References (15)

• Anales Ci. Parag. ser. 1, 5:3. 1905
• Bortolotto, I. M., et al, 2018, Lista preliminar das plantas alimenticias nativas de Mato Grosso do Sul, Brasil. Iheringia, Serie Botanica, Porto Alegre, 73 (supl.):101-116
• Darley, J.J., 1993, Know and Enjoy Tropical Fruit. P & S Publishers. p 132
• Facciola, S., 1998, Cornucopia 2: a Source Book of Edible Plants. Kampong Publications, p 42
• Gonzalez, C., et al, 2014, Main properties of steviol glycosides and their potential in the food industry: a review. Fruits, Vol. 69, p. 127-141

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