A bit about stevia

A bit of history:

1. Stevia is an extract from a plant which is used as a sweetener. It is indigenous to the Amambay Mountain region.
2. The Guarani Indians of South America have used stevia for centuries as a sweetener. 
3. The use of stevia was recorded in Spanish historical documents in the archives of Paraguay in Asuncion. 
4. About 1900 Dr. Moises Santiago Bertoni, director of the College of Agriculture in Asuncion, wrote of stevia: " A fragment of the leaf only a few square millimeters in size suffices to keep the mouth sweet for an hour;..."
5. In 1931, two chemists in France isolated the sweet compound, and called it stevioside but a US Dr.  Hewitt G. Fletcher found it had no use. (Which I find odd since sugar was still expensive about this time.)
6. In the 1960s the Japanese strictly regulated or outright banned artificial sweeteners, and discovered stevia to be the best substitute.  
7. By 2010 I started seeing stevia available in the US.

Source: Stevia.net

1. Stevia leaves have about 12% level of sweetener. Refined stevioside is about 81-90% sweetener. 
2. Stevia, though it's from the tropics, is adaptable, and can be grown from southern Canada down to Floria. 
3. Stevia does best in rich, loamy soil. 
4. Stevia feeder roots tend to be near the surface of the ground, so it's best to use mulch to protect them.  
5. There are several companies that will ship you live plants. See http://www.stevia.net/growingstevia.htm#sources. 
6. Plants are susceptible to cold during their young stage, so consider it a warm weather plant. Roots can also be susceptible to excess moisture, so make sure the soil is well-drained.