Rautahi

Botanical name: Carex lessoniana
Synonyms: Carex polystachya
Common name(s): Rautahi, Cutty grass

Plant facts:
A robust rhizomatous native sedge that forms dense tussocks and spreading colonies in wet habitats. Its bright green foliage and arching flowering stems make it a valuable species for wetland restoration and erosion control.

Natural habitat:
Margins of peat swamps, wetlands, wet alluvial forest and damp lowland habitats from coastal to lowland areas.

Growing environment:
Tolerates a wide range of soil and moisture conditions but performs best in consistently moist to wet soils. Prefers partial shade but will grow in full sun where moisture is reliable.

Endemic distribution:
Endemic to New Zealand. Widespread throughout the North Island and common in the northern half of the South Island, becoming more sporadic further south.

Height:
500 mm – 1.5 m tall

Width:
Forms large tussocks and spreading colonies via rhizomes.

Flowering:
October – December

Fruiting:
December – April

Uses:

• Wetland restoration
• Riparian planting
• Stream bank stabilisation
• Erosion control
• Native revegetation
• Rain garden planting
• Wildlife habitat creation

Appearance:

Growth habit:
Robust rhizomatous sedge forming dense tussocks and colonies.

Leaves:
Bright green to dark green, numerous, double-folded and typically longer than the flowering stems. Leaves are 3.5–8 mm wide with rough margins.

Flowers:
Flower spikes are arranged in dense clusters. Male spikes occur near the top of the stem, while the larger female spikes hang from slender stalks lower down the stem.

Fruit:
Produces small brown nuts enclosed within inflated green to reddish-brown utricles which aid dispersal.

Ecology:
An important component of wetland and swamp ecosystems, providing habitat and stabilising saturated soils. Seeds are dispersed by wind and animals.

Associated habitats:
Peat swamps, wetlands, wet forest margins, alluvial forest, stream edges and damp lowland shrublands.

How to grow:
Easy to cultivate from fresh seed or division. Plant in moist to wet soils in full sun or partial shade. Suitable for wetland margins, ponds, swales and damp garden areas.

Propagation:
Readily propagated from fresh seed and by division of established plants.

Cultural use:
Rautahi has long been recognised as a characteristic sedge of New Zealand wetlands and swamp forests.

Garden value:
A vigorous and attractive native sedge valued for its lush foliage, adaptability and ability to stabilise wet soils. An excellent choice for wetlands, riparian plantings and naturalistic native landscapes.