The herb garden is a place where tradition rules — the same plants having been grown for hundreds of years — so it is surprising how rapidly Stevia (Stevia rebaudiana) has earned a place there. When I first started gardening, it was unheard of and only a few years ago I had to buy a plant by mail order. Now it is commonly available in garden centers, where it is sometimes sold under the name Sweet Leaf. This meteoric rise (by the standards of the herb garden) has come about because it has a unique and intensely sweet flavor unlike any other common plant. This sweetness is due to several chemicals (mainly stevioside and rebaudioside) which are 200 to 300 times sweeter than sugar, but don’t contain any calories.
This South American herb is a tender perennial and my garden in zone 9 is close to its limit for cold hardiness. Plants usually survive the winter here, though a particularly cold winter would probably kill it off. In colder climates it can be brought inside for the winter and will survive as a houseplant if kept in a sunny place. You might also leave it outside until it dies back and then put it in a cool garage where it will stay dormant for the winter.
Stevia can be grown from seed and is sometimes grown as an annual, but superior strains must be propagated vegetatively. It can be grown from cuttings fairly easily, but I find it is best to divide the plants in spring when they first start to emerge. These break up into separate plants very easily and grow quite rapidly.
This is a tropical plant and requires short days to flower, so in northern areas it only flowers late in the year. It often produces seed abundantly, but it is only worth saving seed that is black or dark brown, as lighter colored seed isn’t usually viable.
A Stevia leaf is 300 times sweeter than sugar and can be used as a sweetener in a variety of ways. To use in baking you simply dry the leaves and crush them to a powder. A large tablespoon of powder is equal to a cup of sugar.
Stevia is most often used to sweeten herbal tea. You can add a couple of leaves to a cup, but the sweetness doesn’t seem to come out very well. A better way is to steep a quarter cup of powder in a cup of water for 24 hours. Keep the liquid in the fridge and use as much as needed for tea.
My children roll up a leaf of stevia in a couple of leaves of spearmint to make a natural candy and I have started doing the same thing.
There was once some controversy about the safety of Stevia, with some claiming that various constituents were toxic. As a result it was banned from use as a food additive in the USA and Europe for a long time (though it could be bought as a food supplement). These concerns have now been largely dispelled and it is undoubtedly less toxic than approved artificial sweeteners. It has been suggested that previous bans were promoted by manufacturers of more toxic artificial sweeteners (hard to believe, I know). Now that Coca Cola/Cargill and Pepsi have developed Stevia sweeteners, it has been approved for use. If you Google “Why was Stevia banned” you can read the whole sorry story.
Stevia is now available to add to your garden. You can find it by browsing under Herbs: