Oblong-leaved sundew

How to recognise it

Growth habit

Small perennial rosette plant, 5–10 cm tall, with obliquely upright leaves. In shallow water it sometimes forms a short stem with new rosettes above.

Leaf

An elongated, spoon-shaped blade of about 1 cm, gradually narrowing into a long, hairless stalk. The blade is covered with red tentacles, each tipped with a glistening drop of sticky mucilage.

Flower

White, about 5 mm, with five petals, a few together on a one-sided spike. The flower stem arises from the side, below the rosette, curves upwards and grows only a little taller than the leaves. The flowers only open in sunshine. Flowers in July–August.

Fruit/Seed

Small capsules with numerous tiny seeds, ripening in late summer.

Roots

Short, weak and little branched: they anchor the plant and take up water; nutrients come mainly from its prey.

Confusion with

Round-leaved sundew has round leaf blades lying flat on the ground and a flower stem that rises from the centre of the rosette and grows much taller, up to 20 cm. Great sundew has longer, narrower leaves and is extremely rare here.

Flowering: July–August

Why grow it?

• One of our few carnivorous plants: a living nature lesson in how plants adapt to poor soil.
• A characteristic species of wet heath and heathland pools: where it grows, the water is still acidic, clean and nutrient-poor.
• Catches small midges and flies with its sticky ‘dewdrops’, which sparkle beautifully in the sun.
• The red tentacles and little white flowers make a small bog planter or marsh pot a real eye-catcher.
• A pioneer that returns where conservationists strip the heath: a sign that this management works.

Oblong-leaved sundew: where does it grow best?

• In the wild: wet heath, damp, bare sandy and peaty ground, edges of heathland pools and small bogs, wheel ruts and stripped areas, sometimes in shallow water.
• Full sun: in shade it loses its red colour and grows poorly.
• Always wet, acidic and very nutrient-poor soil; it cannot tolerate lime or fertiliser.
• In the garden: a bog planter or small marsh tub filled with rainwater, or a pot standing in a saucer of rainwater, outdoors in a sunny spot.

Goes well with

• Round-leaved sundew: Its sister species, for a bog planter with two kinds of sundew; also only from a nursery.
• Cross-leaved heath: A low heather with pink bells for the edge of a small, wet, acidic bog bed.
• Common cottongrass: White tufts in spring, on the same wet, acidic soil.
• Marsh violet: A low violet for wet, acidic soil, flowering before the sundew.

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

1. Only buy oblong-leaved sundew from a nursery specialising in carnivorous plants, with plants raised there. Never pick or dig up plants or seed from the wild: the species is rare and legally protected.
2. Use a nutrient-poor, acidic growing medium, for example lime-free silver sand mixed with sphagnum peat or a peat-free alternative for carnivorous plants. Never ordinary potting compost or garden compost.
3. Plant in April–May in a plastic or glazed pot, or in a bog planter lined with pond liner, in full sun.
4. Stand the pot in a saucer with 1–2 cm of rainwater, so the medium always stays wet.
5. Only use rainwater or demineralised water: tap water contains lime and salts that slowly kill the plant.
6. Plant a few plants 5 cm apart for an attractive little group.

Care

Water

Keep the medium wet at all times with rainwater; in summer a thin layer of water can stand in the saucer. Never let it dry out.

Feeding

Never: fertiliser burns the roots. It gets its food from the insects it catches.

Feeding insects

Not needed outdoors: it catches enough midges and flies. Never give it pieces of meat.

Weeding

Carefully pull out grasses, rushes and birch seedlings, and trim back moss that grows too vigorously, or it will be smothered.

Repotting

Every two to three years in spring, into fresh medium: over time old medium breaks down, becomes less airy and richer in nutrients.

Tip: Keep a water butt or bucket of rainwater ready and never use tap water: that is the great secret of a healthy sundew. Leave the plant outdoors in winter too, because without winter cold it starts poorly in spring.

Pruning and mowing

When: Not needed.

How:

• Do not cut anything off: old leaves die back by themselves and decay into the medium.
• If you do not want seed, cut off the spent flower stem; otherwise leave it.
• In spring, only remove dead, mouldy remains, using tweezers.

Caution: Always leave the winter bud in the centre of the plant alone.

Pruning calendar and basic rules

Propagation

Seed

In autumn or early spring, scatter seed from cultivated plants on wet, acidic medium and do not cover it. The seed needs a cold period: leave the pot outdoors over winter.

Leaf cuttings

In summer, lay a healthy leaf on wet medium under a clear lid; after a few weeks small plantlets appear on the leaf.

Winter buds

Plants that have formed several winter buds in autumn can be carefully separated in spring.

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

Hardy to −25 °C.

• In autumn it withdraws into a small, green winter bud at or just below the surface; the leaves die back.
• Fully hardy, and it actually needs the winter cold: leave the pot or bog planter outdoors.
• Keep the medium wet in winter too: freezing is no problem, drying out is.
• In March–April the winter buds start growing again.

Diseases and pests

• Tap water: Brown leaf edges and ailing plants are usually caused by lime or salts from tap water. Flush the medium with rainwater or repot into fresh medium.
• Drying out: A single day of drought in summer can already be fatal. Always stand the pot in a saucer of water.
• Aphids: Sometimes on the flower buds. Rinse them off gently with rainwater.
• Grey mould: On dead parts in low light or in a damp, stagnant corner. Remove dead leaves and move it to an airy, sunny spot.
• Smothered by moss: Sphagnum and other mosses can overgrow it. Trim the moss short around the rosette.

Through the year

• January: Dormant as a winter bud: the cold is needed.
• March: The winter buds start to grow. Repot if needed.
• April: Plant in a bog planter or pot. Rainwater in the saucer.
• May: New leaves with sticky drops: the first midges are caught.
• June: Full growth. Always keep wet with rainwater.
• July: Flowers in sunny weather. Take leaf cuttings.
• August: Last flowers. Never let it dry out.
• September: The seed ripens. Collect seed from your own cultivated plants.
• October: Winter buds form. Sow and leave the pot outdoors.
• November: Dormant. Keep the medium wet.

Did you know?

• The name Drosera comes from the Greek droseros, ‘dewy’: the sticky drops on the leaves look like dew that does not dry in the sun. The name sundew refers to the same thing.
• Charles Darwin studied sundews for years and devoted a large part of his 1875 book Insectivorous Plants to them.
• When an insect touches the tentacles, they slowly bend towards it and hold it fast; within a few days the prey is digested until only its hard outer shell is left.