Kermadec Sedge

Botanical name: Carex kermadecensis
Synonyms: Carex forsteri subsp. insularis
Common name(s): Kermadec sedge

About:
A robust subtropical sedge endemic to the remote Kermadec Islands. This distinctive species forms large lush tussocks with broad arching foliage and erect clustered flower spikes. It is the only naturally occurring Carex species on the Kermadec Islands.

Natural habitat:
Coastal forest, rocky volcanic slopes, seabird nesting areas and rubble-covered shaded coastal sites.

Growing environment:
Prefers warm humid frost-free conditions in sheltered semi-shaded positions with moist fertile free-draining soil.

Endemic distribution:
Endemic to the Kermadec Islands, where it is known from Raoul and Macauley Islands.

Height:
Culms up to 450 mm tall, with foliage often taller.

Width:
Forms broad dense tussocks over time.

Flowering:
October – January

Fruiting:
October – May

Uses:

• Subtropical native gardens
• Frost-free coastal landscapes
• Specialist sedge collections
• Shaded feature planting
• Botanical collections
• Native habitat restoration in warm climates

Appearance:
Forms robust yellow-green to green tussocks with broad double-folded leaves 7–10 mm wide that arch well beyond the flowering stems. Inflorescences consist of 5–10 erect light brown spikes, often compound and clustered near the stem apex. Female spikes may reach 5.5 cm long. Utricles are grey-brown with reddish flecks and sharply bifid beaks.

Ecology:
Frequently associated with seabird colonies where nutrient enrichment and soil disturbance favour establishment. Seeds enclosed within inflated utricles are dispersed by wind and animals.

Associated habitats:
Coastal forest margins, volcanic boulder fields, seabird colonies and sheltered coastal scrub.

How to grow:
Best grown in a warm sheltered frost-free position with partial shade and consistently moist soil. Protect from cold temperatures and drying winds. Mulching helps retain moisture and humidity around the roots.

Propagation:
Propagated from fresh seed or by division of mature clumps.

Cultural use:
An important component of the unique flora of the isolated Kermadec Islands and of botanical significance because of its highly restricted distribution.

Garden value:
A bold and attractive native sedge valued for its lush subtropical appearance, broad arching foliage and rarity. Excellent for sheltered frost-free native gardens and coastal plantings where a strong textural feature is desired.