Forked Sundew

Botanical name: Drosera binata
Synonyms: Drosera dichotoma, Drosera intermedia, Drosera cunninghamii, Drosera flagellifera
Common name(s): Forked Sundew, Fork-leaved Sundew, Scented Sundew

About:
Forked Sundew is a large perennial carnivorous herb distinguished by its erect, repeatedly forked leaves. Each narrow leaf divides into two or more spreading branches lined with glistening glandular hairs that trap insects. It is one of the most vigorous and easily recognised sundews in New Zealand and may form conspicuous colonies in open, waterlogged bogs and acidic pasture.

Natural habitat:
Occurs from coastal areas to subalpine elevations in bogs, peatlands, swamp margins and poorly drained pasture over acidic soils. It is most common in coastal and lowland wetlands but may extend into cooler upland habitats.

The species favours open, sunny ground with a permanently high water table and little competition from taller vegetation. It often becomes locally abundant after fire, when dense scrub and sedges have been reduced.

Growing environment:
Requires full sun or bright open conditions, a strongly acidic nutrient-poor substrate and consistently wet roots. It grows naturally in waterlogged peat, sphagnum moss and poorly drained mineral soils.

Only rainwater, distilled water or similarly low-mineral water should be used in cultivation. It is intolerant of fertiliser, lime, ordinary potting mix, alkaline soils and mineral-rich tap water.

Endemic distribution:
Indigenous but not endemic to New Zealand. It occurs on the North, South, Stewart/Rakiura and Chatham Islands. It is also native to Australia.

Height:
Approximately 15–60 cm

Width:
Approximately 20–40 cm, with established colonies spreading more widely

Flowering:
Usually spring to summer

Fruiting:
Usually summer to early autumn

Uses:
• Specialist carnivorous plant collections
• Native bog gardens
• Wetland restoration
• Educational displays
• Botanical collections
• Study of carnivorous plant ecology

Appearance:
Growth habit:
A perennial herb arising from a short underground rootstock with long, fleshy roots. The plant produces a cluster of upright or arching leaves that may lean against neighbouring vegetation. In cold climates the above-ground foliage may die back during winter before resprouting in spring.

Leaves:
Leaves are long, slender and upright, commonly 15–60 cm tall. Each leaf begins as an undivided stalk before splitting into two branches, producing the characteristic T-shaped form. Some plants divide again to form four or more antler-like tips.

The leaf surface and margins are densely covered with stalked glandular hairs. Foliage is usually green to yellow-green but may become bronze or red under strong sunlight.

Carnivorous glands:
The leaf glands produce drops of clear, sticky mucilage that glisten like dew. Small flies, moths, midges and other insects become trapped when they land on the leaf.

The surrounding tentacles gradually bend toward the prey, increasing contact with the digestive surface. Enzymes then break down the soft tissues, allowing the plant to absorb nitrogen, phosphorus and other nutrients that are scarce in bog soils.

Flowers:
Relatively large white flowers are produced on tall, leafless stalks that rise above the trapping leaves. This separation reduces the likelihood that visiting pollinators will become caught.

The flowers may be lightly scented and are generally borne in small clusters. Each has five broad white petals surrounding a yellowish centre.

Fruit:
The fruit is a small dry capsule that splits open at maturity.

Seeds:
Seeds are minute and produced in large numbers. They are dispersed mainly by wind, with water movement likely assisting their spread through wetlands.

Ecology:
Forked Sundew is an obligate wetland plant and is strongly associated with permanently wet, acidic habitats. Carnivory allows it to survive in soils where available nitrogen and phosphorus are extremely limited.

Its upright forked leaves occupy a different trapping zone from the low rosettes of smaller sundews, enabling it to capture insects flying above the ground surface. The plant contributes to nutrient cycling by transferring nutrients from captured animals into bog vegetation and peat.

Fire may temporarily benefit populations by removing shading vegetation and exposing wet peat or mineral soil. Plants can regenerate from their persistent roots, while seed establishes readily on newly opened ground.

Associated habitats:
Peat bogs, sphagnum wetlands, swamp margins, acidic pasture, pakihi, wet heathland and recently burned scrub. Associated plants may include sphagnum mosses, mānuka, tangle fern, sedges, rushes, bladderworts and other native sundews.

How to grow:
Grow in full sun in a deep pot filled with an acidic, nutrient-poor medium. Suitable substrates include live or dried sphagnum moss or a mixture of unfertilised peat and washed silica sand or perlite.

Stand the pot in a shallow tray of rainwater or distilled water so the root zone remains permanently wet during active growth. Deep pots are preferable because the plant develops long fleshy roots.

Never apply fertiliser or lime. Do not use ordinary compost or potting soil. In cold regions, plants may die back naturally during winter; keep the medium wet to moist and allow new growth to emerge in spring.

Propagation:
Forked Sundew is readily propagated from seed, root cuttings or division.

Surface-sow fresh seed onto wet acidic medium without covering it. Maintain bright light, high humidity and constant moisture until germination.

For root cuttings, remove a small section of healthy fleshy root during dormancy or early spring. Cut it into short lengths, lay the pieces horizontally on wet sphagnum or peat and cover them very lightly. New plantlets may emerge from the root sections.

Established clumps may also be divided carefully, ensuring each section retains healthy roots and an active growing point. Leaf cuttings may occasionally produce plantlets when floated in clean water under bright light.

Cultural use:
No specific traditional Māori uses are widely documented for this species. It is nevertheless an important and distinctive member of Aotearoa’s bog and wetland flora.

The name Drosera comes from a Greek word meaning “dewy”, referring to the sparkling mucilage on the leaves. The specific name binata derives from Latin words meaning paired or twice-born, describing the leaf’s division into two branches.

Garden value:
One of the most dramatic and rewarding sundews for specialist cultivation. Its tall antler-like leaves, glistening insect-trapping glands and white flowers make it an excellent focal plant for bog gardens and carnivorous plant collections.

It is generally more vigorous and forgiving than many smaller sundews, provided it receives pure water, strong light and a permanently wet, nutrient-poor growing medium.