Saturday, September 18, 2010
Herb of the Week -- Stevia
The herb of the week is Stevia (stevia rebaudiana).
Technically, Stevia describes about 250 plants closely related to asters and sunflowers, which are mostly native to South America, but Stevia Rebaudiana, also know as Sweetleaf or Sugarleaf, is commonly referred to simply as Stevia, and it is the plant I want to address this week.
This plant was a fluke for us. I had seen something online where I could request a free sample of a non-sugar sweetener. Always looking for new ways to eat sweet without adding ‘junk to the trunk‘, as it were, I sent for some and when they arrived I read about the product. Seems they were a crystal made from a plant called Stevia. So, when I saw Stevia plants at the nursery this spring, I thought, “What the heck, let’s try some”.
A bit of history here, Stevia was banned from the United States for a while, then, when it was allowed, the FDA only allowed it to be sold as a nutritional supplement, or an additive, they didn’t allow it to be called a sweetener. It wasn’t until December of 2008, that they finally allowed it to be sold as a sweetener.
Stevia is 30 to 40 times as sweet as sugar, and it appears, that there is a rapidly growing market for this plant. It is widely used worldwide, in Japan since the 1970’s, in China since the 1980’s, and more recently Canada, and is gaining acceptance in the US as well.
The plant is somewhat unattractive and unassuming , but seems to be very hardy and low maintenance.
There does not seem to be much information available as to the origin of the name, although there is a bit of controversy over the pronunciation. While some people pronounce it Stee-vee-uh and others prefer Steh-vee-uh, it seems the proper latin pronunciation is Stay-vyuh. However, like many words, this one has become Americanized and the most common pronunciation here is Stee-vee-uh.
So, now that we've got that out of the way, let’s talk about growing it.
Organic gardeners in particular should find stevia an ideal addition to their garden. Though nontoxic, stevia plants have been found to have insect-repelling tendencies. Their sweetness seems to be a kind of natural defense mechanism against aphids and other bugs . Perhaps that's why crop-devouring grasshoppers have been reported to bypass stevia under cultivation.
While tolerant of most soil types, Stevia prefers a sandy loam or loam. Any well-drained soil that produces a good crop of vegetables should work fine. Stevia will grow well in partial shade, but will do equally well in full sunlight.
In North America, Stevia survives winters only in the warmest areas such as southern California, Florida, and Mexico. In colder areas, Stevia is planted after the last frost and treated as an annual.
Planting from seeds is difficult and can be discouraging, so I would recommend buying some plants from a nursery. The ambitious gardener may then take cuttings and winter them inside for next year. The less ambitious gardener, or the one with less room than ideas, like myself, may finds it easier, and ultimately more rewarding to simply buy new plants next spring.
Stevia prefers well drained soil, and care should be taken to avoid water puddling or pooling around the roots, as it seems particularly prone to root rot.
Stevia will do well in a container garden, or a pot as long as it is at least 12” deep and 12” in diameter.
Plants should be spaced at least 18” apart, as they can reach up to 30”” tall, and, with the right tricks can bush out and grow 18-24 inches wide. Not knowing those tricks, I have three Stevia plants that are tall and spindly and did not bush out very much at all.
Pinching off the tops of the main stem, and then subsequent stems, will result in a shorter bushier plant. Flowers should be removed as soon as the buds appear. , Because it is a member of the “Aster” family, once flowering has begun, not a single normal leaf will be produced. Removing flower heads will not encourage new leaves.. Failure to harvest plants before several flowers have opened, will allow these flowers to impart a bitter/dirty flavor to the leaves.
Your strategy for harvesting your Stevia plant will depend on the region you live in and whether or not you intend the plant to overwinter. The later in the year you can wait to harvest, the sweeter the leaves will be, as the plant continues to produce steviocides. A full harvest will probably occur in late September or early October.
If you intend to keep your plant over the winter, remove the leaves from the top of the stem down to about 4-6” above the ground. If, like me, you plan to replant, the just cut the entire stalk.
The stem is not nearly as sweet as the leaves, but does have some steviocides in it, feel free to experiment by using it to stir your tea.
The leaves are traditionally dried, and the powdered, in a blender or coffee grinder. The powder can then be used as a sweetener for tea, or other beverages, or in many other recipes.
Not all Stevia plants are created equal, so you will want to experiment with yours, but it has been claimed that one teaspoon of powder can equal the sweetness of one cup of sugar.
Of course, the green flecks can be unattractive if using Stevia to sweeten something like whipped cream, for example, so there are other ways to extract the flavor.
Hot liquid will release the steviocides, so steeping the leaves in hot water or, whirling them in a blender with hot water, and then straining the bits will give you a sweet water.
One article I read, suggested heating a cup of vodka to just below boiling and then adding it to one cup of finely chopped leaves. After letting it stand for 24 hours and straining the leaves out, the resulting liquid can be used, a few drops at a time, to sweeten a variety of beverages, or for many other cooking applications, where precise measurement is not critical.
Of course, Stevia can be picked as needed throughout the growing season, and One fresh stevia leaf is enough to sweeten a cup of tea or coffee or a glass of lemonade. Or you may try adding the leaves to baked beans, barbecue sauce, salad dressings, etc.
Medicinally, Stevia is fairly new to the scene, various studies have found the leaf to contain proteins, fiber, carbohydrates, iron, phosphorus, calcium, potassium, sodium, magnesium, zinc, vitamin A, Vitamin C and an oil which contains 53 other constituents. Quality Stevia leaves and whole leaf concentrate are nutritious, natural dietary supplements offering numerous health benefits.
It is sold in some South American countries as an aid to people with diabetes and hypoglycemia. Studies have also indicated that Stevia tends to lower elevated blood pressure but does not seem to affect normal blood pressure. It also inhibits the growth and reproduction of some bacteria and other infectious organisms, including the bacteria that cause tooth decay and gum disease. This may help explain why users of Stevia enhanced products report a lower incidence of colds and flu and why it has such exceptional qualities when used as a mouthwash or added to toothpaste. Many people report significant improvement in oral health after adding Stevia concentrate to their toothpaste and using it, diluted in water, as a daily mouthwash.
There doesn’t seem to be a lot of Magic, superstition, or folklore surrounding Stevia, perhaps because it is still so new on the local scene, although Brazilian and Paraguayan native cultures have been using it for centuries.
The plant was an experiment for us this year, we have used the leaves to sweeten herbal teas and have been pleased with the results.
I look forward to playing with it more in the future and intend to make it a regular plant in our garden.