Round-leaved sundew

How to recognise it

Habit

Small, flat leaf rosette 3–8 cm across. The flowering stem grows 5–25 cm tall.

Leaf

Round blades 0.5–1 cm across on long, hairy stalks, covered with red glandular tentacles, each with a sticky droplet that glistens like dew in the sun.

Flower

Small white flowers about 5 mm across on a leafless stem rising upright from the centre of the rosette. They form a one-sided spike curled at the tip and open only in sunshine.

Fruit/Seed

A small capsule with dozens of tiny, spindle-shaped seeds, spread by wind and water.

Roots

Weak and little branched: the plant gets part of its nutrients from captured insects.

Look-alikes

Oblong-leaved sundew has elongated, spoon-shaped leaves and a flowering stem that arises from the side, below the rosette, and then curves upwards. Great sundew has long, narrow leaves and is extremely rare in Belgium.

Flowering: June–August

Why grow it?

• One of our few carnivorous plants: a living wonder of nature to show children.
• It catches small midges and flies, but is completely harmless to people and animals.
• An indicator of healthy, nutrient-poor wetland: where it grows, the soil has been neither fertilised nor drained.
• In a bog garden or a small rain-fed wetland you can follow this rare little plant up close, using cultivated plants.
• The glistening droplets are beautiful in the morning sun, from spring until autumn.

Round-leaved sundew: where does it grow best?

• In the wild: wet heath, raised bog, edges of heathland pools, damp sandy spots on heaths and carpets of sphagnum moss.
• Full sun: in shade or among tall vegetation it soon disappears.
• Wet, acid and very nutrient-poor soil: sphagnum, peat or bare, wet sand. Never lime or fertiliser.
• In the garden: only in a bog garden, a small lined wetland or a pot standing in a saucer of rainwater, in a sunny spot.

Goes well with

• Sphagnum moss: The natural growing medium: it holds water and stays acid and nutrient-poor.
• Cross-leaved heath: Pink bells in summer, on the same wet, acid soil.
• Common cottongrass: White tufts in May–June, typical of wet heath.
• Cranberry: Creeps over the sphagnum and bears red berries.

Round-leaved sundew: when and how to plant it?

1. Buy only cultivated plants or seed from a nursery specialising in carnivorous plants. Never pick or dig up sundew in the wild: the species is rare and protected.
2. Make a bog garden: a tub or rigid pond liner without drainage holes, or a hole lined with pond liner, filled with a mixture of sphagnum moss and lime-free sand.
3. Plant in April–May, in a spot that gets at least half a day of full sun.
4. You can also sow: scatter the seed on wet sphagnum in autumn or winter and leave it outdoors in the cold. Don’t cover it, as it needs light to germinate.
5. Keep everything soaking wet with rainwater. Never use tap water: the lime and salts in it will eventually kill the plant.
6. Don’t give it fertiliser and don’t feed it meat: it catches enough insects by itself.

Care

Water

Rainwater only. The soil must always be wet; in summer a pot can stand in a saucer with 1–2 cm of rainwater.

Feeding

Never. Fertiliser and rich soil kill the plant or let moss and grass overgrow it.

Weeding

Carefully pull out grasses, rushes and tree seedlings so that the rosettes stay in full sun.

Sphagnum

If the moss grows over the rosettes, trim it back a little with small scissors.

Self-seeding

Let the flower stems ripen their seed: in a good bog garden new plants appear by themselves.

Tip: Put a water butt next to your bog garden: sundew doesn’t die of cold, but it does die of tap water and drought.

Pruning and mowing

When: Not needed. You only keep the surroundings open when the little plants become overgrown.

How:

• Simply leave dead leaves where they are: they break down into new peaty soil.
• Trim away moss or grasses that shade the rosette.
• Leave the flower stems until the seed has ripened.

Pruning calendar and basic rules

Propagation

Seed

Sow in autumn or winter on wet sphagnum and stand it outdoors: the seed needs a cold period. Seedlings appear in spring and grow slowly.

Leaf cuttings

A leaf laid flat on wet sphagnum under a clear lid sometimes produces tiny plants after a few weeks. Only with cultivated plants.

Round-leaved sundew: how does it get through the winter?

Hardy to −30 °C.

• In autumn it draws in its leaves and forms a small, tight winter bud on the moss.
• In this resting state it survives severe frost; in spring the bud grows again.
• Never bring it indoors into the warmth: without a winter rest it dies.

Diseases and pests

• Tap water: Brown, withering rosettes after a few months: often caused by lime and salts. Flush the container with plenty of rainwater and use only rainwater from then on.
• Drying out: A single hot, dry week can kill the little plants. In summer, check the water level daily.
• Overgrowth: Grasses, rushes or sphagnum shade out the little plants. Thin them out carefully and regularly.
• Aphids: Sometimes on the flower stems. Rinse them off with rainwater; don’t use sprays.

Through the year

• January: Winter rest. No warmth, but keep wet with rainwater.
• March: The winter bud starts growing. Trim grass and moss around the plants.
• April: New leaves with droplets. Plant in a bog garden.
• May: Busy catching small insects. Check the water every day.
• June: Flower stems appear; first flowers in sunny weather.
• July: Flowering. Top up with rainwater in dry weather.
• August: Last flowers; seed ripens.
• September: Collect seed or let it fall.
• October: Leaves get smaller; the winter bud forms. Sow on wet sphagnum.
• November: Winter bud. Leave the container outdoors.

Did you know?

• Charles Darwin studied sundews for years and devoted a large part of his book on insectivorous plants (1875) to them.
• The tentacles slowly bend towards a captured insect and the leaf can partly fold around it; enzymes then digest the prey.
• The name Drosera comes from the Greek droseros, dewy. The French name rossolis comes from the Latin ros solis, ‘dew of the sun’.