Stevia, the leafy green sweetener

Fifteen years ago at a horticultural show in Chennai, I came across the Stevia plant (Stevia rebaudiana bertoni) for the first time. The curator gave me a leaf to taste and I could hardly believe the intense sweetness of the little leaf. I bought a couple of inexpensive saplings of this plant and have been growing them ever since.

Used to treat diabetes

A perennial shrub of the chrysanthemum family, Stevia grows wild in Paraguay and Brazil, where it is used to treat diabetes. It is said to stimulate the pancreas to produce insulin, though scientific studies are still sparse. Native Indians have been using it as a sweetener and as a medicinal herb for centuries.

The plant contains glycosides and stevioside in its leaves, which account for the incredible sweetness.

The powder of the dried Stevia leaf is 12 times sweeter than sugar and an extract is 300 times sweeter. Since this sweetness is not because of carbohydrates, it adds negligible calories to your diet.

The plant can be grown in most soil types but prefers well-drained, sandy loam with plenty of organic manure. A handful of bone meal would satisfy the nutrient requirements.

The seeds germinate poorly, so it is easier to buy a plant from the local nursery and multiply it later from tip cuttings. Space the plants on the ground 40 cm apart and 60 cm between rows. A pot of 30 cm diameter can take one plant.

Stevia has shallow feeder roots, so mound the soil around the base. Regular watering is important. High nitrogen fertilizer produces lush growth of leaves that are not very sweet, so an organic fertilizer low on nitrogen is better for side dressing.

Prune and harvest

Harvest by pruning and plucking out the leaves. Pruning encourages side branching resulting in bushier plants.

The plant produces small white flowers. Nip the flower buds to encourage leaf growth.

When the plant gets straggly, cut it just 15 cm above ground level and let it to grow back. With care, the plant lasts for two to three years. The plants are not affected by common pests; perhaps their intense sweetness is a deterrent.

Stevia is grown commercially in many countries including India. Japan introduced stevia in its market in the 1970s, banning many artificial chemical sweeteners and is now its biggest consumer in the world.

Dried stevia leaf powder and extracts are good sugar substitutes in many recipes. They are heat stable and can be used for cooking and baking but do not caramelise as sugar does.

The green of the leaf powder may impart a slight colour depending upon the quantity used.