Stevia

Stevia: how do you recognise it?

Habit

Upright, branching herb 40–60 cm tall and 40 cm wide, with a woody base on older plants.

Leaves

Narrowly lance-shaped to inverted egg-shaped, 3–5 cm long, with a toothed edge in the upper half; fresh green and soft.

Flower

Small, white, tubular flowers in loose clusters, in September–October.

Flavour

The leaves are sweet, with a slight herby aftertaste, especially if overused.

Roots

Fibrous and shallow: the plant is easy to repot, but does not tolerate wet feet.

Flowering: September–October · Harvest and fruit: August–October · Plants: May–June · Pruning: April, June–July and October

Why grow it?

• The leaves are many times sweeter than sugar: a few leaves are enough for a cup of tea or a glass of lemonade.
• Easy to grow in a pot on a sunny patio or on a windowsill.
• Pretty, fresh foliage and small white flowers in autumn.
• An unusual plant for the herb garden and a fun one to grow with children.
• Cuttings root easily, so you can keep it going with little effort.

Stevia: where does it grow best?

• Full sun in a warm, sheltered spot; in sun the leaves are at their sweetest.
• Loose, humus-rich and free-draining soil: sand or loam, acid to neutral.
• Normally moist: do not let the soil dry out, but avoid wet feet.
• Allow 30–40 cm between plants; in a pot, at least 25 cm across.
• It is a warmth-loving plant: below 10 °C it hardly grows.

Light

Sun

Soil type

Sand or loam

Acidity

Acid or neutral

Moisture

Normal

Size

0.6 m tall, 0.4 m wide

Hardiness

Frost tender: overwinter indoors (above 2 °C)

Goes well with

• Mint: Use together in tea; keep the mint in its own pot, as it spreads.
• Lemon balm: Refreshing leaves for the same drinks.
• Lemon verbena: A summer plant for tea that needs the same warmth.
• Basil: Same season, same sunny, sheltered spot.

Stevia: when and how to plant it?

Plant in May–June.

1. Plant only after the Ice Saints, in May–June, when nights are warm and frost is over.
2. Choose a pot at least 25 cm wide with drainage holes and an airy compost with a little garden compost, or a hole in a warm border.
3. Set the plant at the same depth as in its pot, 30–40 cm from the next, and firm the soil.
4. Water in generously at once, but do not leave water standing in the saucer.
5. Add a thin mulch of compost or bark around the base.

Care

Water

Keep the soil evenly moist, but not wet. The leaves droop quickly in dry conditions; in a pot, check daily in warm weather.

Feeding

From June to August every 3–4 weeks, an organic or liquid feed; too much feed gives coarse foliage.

Pinching out

From June, pinch out the tips regularly for a dense, bushy plant.

Harvesting

Pick the leaves fresh, preferably before flowering, when they are sweetest. Dry them in bunches and crumble them.

Use

A few leaves are enough for tea or drinks; too many can leave a bitter aftertaste.

Tip: The leaves are many times sweeter than sugar; dry them and crumble them. Grow stevia in a pot in a warm spot and overwinter it frost-free.

Stevia: when to prune it?

Pruning months: April, June–July and October.

When: In April (overwintered plant), from June to pinch out the tips, and in October before bringing it indoors.

How:

• In April, cut the overwintered plant back to 10–15 cm above the ground, just above healthy buds.
• In June–July, pinch out the tips of the shoots regularly, for a dense, bushy plant.
• In October, before bringing it indoors, cut all the shoots back to about 10 cm and harvest the leaves.
• Remove dead or weak stems right at the base.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Cuttings

From May to August: cuttings of 8–10 cm from non-flowering tips, lower leaves removed, in moist compost or water in a warm, bright place. Roots in 2–3 weeks.

Sowing

In March–April under glass at 20–25 °C, on the surface, barely covered: the seed needs light to germinate and often germinates poorly. Cuttings are more reliable.

Stevia: how does it get through the winter?

Hardy to 2 °C: protect in harsh winters.

• Not hardy: the plant needs at least 2 °C and suffers in frost.
• Bring it indoors in October, before the first night frost, to a bright spot at 10–15 °C.
• Water sparingly, do not feed and remove dead leaves.
• Take a few cuttings in summer as insurance: they overwinter easily in a bright room.

Diseases and pests

• Red spider mite: Fine webs and dull leaves in dry, warm air. Mist regularly and rinse the plant with water.
• Aphids: On young tips. Rinse off with water or let the ladybirds do their work.
• Limp or yellow leaves: Usually too dry or too wet. Adjust the watering; make sure the pot has drainage holes.
• Slugs: Young plants are nibbled after planting. Collect the slugs and protect the plant until it is bigger.

Through the year

• March: Sow under glass. Move the overwintered plant to a brighter spot.
• April: Cut back and repot. Take cuttings.
• May: After the Ice Saints, put outside or plant.
• June: Pinch out tips. Start feeding.
• July: Water. Pick leaves. Pinch out tips.
• August: Pick and dry leaves. Take cuttings for the winter.
• September: Flowering. Pick the last leaves.
• October: Cut back and bring indoors frost-free. Water sparingly.

Edible and useful

Leaves (August–October)

The leaves are sweetest at the end of summer, just before flowering, from August to October. Then cut the whole plant down to a hand’s breadth above the soil. A fresh leaf tastes intensely sweet, with a slightly bitter, liquorice-like aftertaste. A few leaves sweeten tea, lemonade, yoghurt or stewed fruit.

Storing

Dry the stems in bunches, hung upside down somewhere airy and dark, then strip off the leaves. Grind them to a green powder or keep them whole. In a closed jar they keep for a year. Stevia is not hardy: overwinter the plant frost-free and in the light, or sow again.

Caution: Dried stevia is 20 to 30 times sweeter than sugar: start with very little, or the bitter aftertaste takes over. It cannot replace sugar in jam or baking, where sugar also gives structure and helps preserve. People taking medication for diabetes or high blood pressure should ask their doctor first.

Eating and using is at your own risk: see the terms of use.

Recipes

• Mint tea sweetened with stevia (Tea · 1 teapot (± 750 ml) · 10 min)
• Stevia powder (Dried · ± 20 g · 20 min + 1 week drying)

Did you know?

• The Guaraní people of Paraguay called the plant ka’a he’ē, ‘sweet herb’.
• Stevia belongs to the daisy family, like the daisy and the sunflower.
• The genus Stevia is named after the 16th-century Spanish botanist Pedro Jaime Esteve.