Shore Spleenwort

Botanical name: Asplenium obtusatum
Common name(s): Shore Spleenwort, Paranako

Plant facts:
A tough coastal fern found throughout southern New Zealand and many subantarctic islands, valued for its thick fleshy fronds and ability to tolerate harsh exposed seaside conditions. This species commonly grows among seabird colonies on windswept cliffs and rocky coastal vegetation.

Natural habitat:
Occurs naturally on exposed coastal cliffs, rocky shorelines, seabird colonies, coastal scrub, and subantarctic island vegetation.

Growing environment:
Full sun to partial shade, Coastal exposure, Free-draining soils & Wind tolerant.
Thrives in rocky coastal environments with excellent drainage and tolerates salt spray and strong winds.

Distribution:
Indigenous to New Zealand, South America, and many southern Atlantic and Pacific islands.
In New Zealand found in the South Island, Chatham Islands, Stewart Island/Rakiura, Snares Islands, Antipodes Islands, Auckland Islands, Campbell Island, and parts of Cook Strait.

Height:
Approximately 0.1–1 m tall

Width:
Forms spreading clumps approximately 0.5–1 m across

Uses:

• Coastal revegetation
• Seaside gardens
• Rock walls and cliff plantings
• Native fern collections
• Container cultivation
• Harsh exposed landscape plantings

Appearance:

Growth habit:
A robust evergreen fern forming dense clumps from a stout woody rhizome often protruding above the ground.

Fronds:
Fronds are thick, leathery, fleshy, and dull green with a simple pinnate structure adapted to exposed coastal environments.

Leaflets:
Pinnae are broad, blunt to slightly pointed, with smooth to finely toothed margins and scales beneath.

Rhizome and stems:
Rhizomes are woody and heavily scaled. Stipes are stout with dark brown bases and green upper portions.

Sori:
Long narrow sori develop beneath the fronds and remain well within the leaflet margins.

Ecology:
An important coastal fern adapted to salt-laden winds, rocky cliffs, and nutrient-rich seabird environments.

Associated habitats:
Often grows alongside coastal shrubs such as Veronica elliptica and Austroblechnum durum, especially near seabird nesting colonies.

Cultural uses:
Known traditionally by the Māori name paranako.

How to grow:
Best grown in free-draining soils in coastal or sheltered sunny positions. Tolerates exposed maritime conditions and responds well to nutrient-rich organic soils.

Propagation:
Propagated from spores or division of established clumps. Slow growing but hardy and long lived once established.

Garden value:
A bold and resilient coastal fern prized for its fleshy architectural fronds and tolerance of harsh seaside conditions. Excellent for coastal gardens, rockeries, pots, and exposed native plantings.