Stevia is the common name for stevia rebaudiana, an herb used as a replacement for sugar or other non-nutritionative sweeteners. The resulting extract from the stevia plant is roughly ten times sweeter than sugar.

Where Stevia Comes From
The stevia plant is native to the Amambay mountain range in Paraguay, South America and was used by the native people in a tea-like beverage as well as for medicinal purposes. It was finally brought to the attention U.S. government in 1918 by a botanist for the U.S. Department of Agriculture.

Worldwide Use
Use of the product is widespread in various parts of the world including South America, China, and Japan. It is far less popular in the U.S. due to a well-entrenched existing sugar industry. Efforts to gain a foothold in the U.S. has been routinely blocked.

Stevia is approved in the United States for sale as a herb but it is not approved for use in "food products". 

Growing Stevia
Stevia is remarkably easy to grow.  We have been seeing plants at local Farmer's Markets.  The plant produces slightly serrated leaves on long stems.  The white flowers are small and delicate.  The leaves are very sweet to the taste.  You can also purchase stevia seeds.  They are so small and fine they almost float away but germinate readily.  The plant shown in the photograph was grown from our seed.   Because the plants tend to hybridize the plant you grow from seed may look different from the plant you find at the local nursery.