Stevia is an exciting choice for the herb garden because of the natural, calorie-free sweetness found in its leaves. Appreciated by diabetics and dieters, stevia is a tender perennial that loves the warm sun and dies back in a freeze. However, in zones 9 and warmer, the roots usually survive the winter and will come back in the spring.
It can overwinter in zone 8, too, with protection. Gardeners in frost-free areas enjoy growing stevia year-round, allowing it to grow into a small shrub. However, vigor declines after the second year, so if you want to harvest the maximum amount of foliage, it pays to replant.
Plant stevia in spring once all chances of frost have passed. This sweet herb grows well in-ground but is also a splendid container plant.