Purchased from Home Depot in 2011. Grew to a height of 3’, at the end of the season I let it die down but left it alone. This year, I have (3) returning plants.
Stevia stems are prone to breakage during high winds. It is recommended to pinch tips out every 3 to 4 weeks for the first month to encourage side branching, resulting in a bushier plant. Grow in a protected area if possible. Supporting the plants with a “corral” made from strings tied to stakes is another strategy.
You can crush the dried leaves by hand using a mortar and pestle or using a coffee grinder. You can use the stevia in this powdered form, adjusting the amount you use to achieve the desired degree of sweetness. Keep in mind that stevia is 30 times more sweet than sugar and a general rule of thumb is 1 generous tablespoon is roughly equivalent to one cup of sugar in terms of the level of sweetness.
You can also make your own stevia simple syrup by adding a cup of warm water to 1/4 cup of fresh, finely-crushed stevia leaves. This mixture should set for 24 hours and then be refrigerated. It works perfectly for sweetening beverages.
Great article on growing Stevia