Stevia Stevia rebaudiana

Sweet leaf is a tender perennial that is a member of the daisy family (Asteraceae) and is native to warm  humid tropical climates of Brazil and Paraguay. This plant grows up to 1 to 2 feet tall and equally as wide, and it is typically grown for its sweet tasting leaves that are ground to make a sugar substitute. The genus name, Stevia, is in honor of a Spanish botanist and physician, Pedro Jaime Esteve. The specific epithet, rebaudiana, is named in honor of Oviodio Rebaudi, a chemist from Paraguay who first extracted the sweet compounds from this plant.

Sweet leaf prefers full sun and will tolerate partial shade and requires moist, well-drained, slightly acidic, organically rich, loamy, sandy soils. It is winter hardy in USDA Hardiness Zones 10 to 11 and thrives in moderate temperatures and humid environment. It is recommended to fertilize the plants about every 4 to 6 weeks during the growing season. In North Carolina, sweet leaf can be grown as an annual and brought indoors before the first frost. The leaves are harvested about 90 days after planting. The best time to harvest is just as it begins to flower. The flowers buds can be pruned to help improve the flavor of the leaves. When harvesting cut the stems about 6 inches above the ground. They are then dried and then can be stored in an air tight container in a cool dry area. The plant can be propagated by stem cuttings or seeds.

The plant is a tender perennial with a fibrous root system and tends to have weak stems that grow up to 12 to 24 inches tall. The leaves are papery, thin, oval to elliptical with slightly serrated margins and measure up to 1-inch long. The flowers are small, white, tubular and appear in clusters of 2 to 6 florets from July to August. The fruits are achenes that contain one seed. 

Stevia is a commercially available sugar substitute that is made from the leaves of this plant. The leaves contain a chemical known as steviol glycosides and has a very concentrated sweet flavor. Reportedly, it is many times sweeter than sugar and has no calories. The fresh leaves can be harvested to make tea; however, dried leaves are usually sweeter than fresh leaves. Once the leaves are dried, they are ground to produce stevia powder. 

In North Carolina, sweet leaf can be grown as annual in an herb garden or as a container planting. The fresh or dried leaves can be used in foods such as beverages, salad, sauces, or to make an herbal teas. 

Insects, Diseases, and Other Plant Problems: It has no known serious insect or diseases problems. Monitor for aphids and spider mites. Overwatering can cause root rot.