Rock Fern

Botanical name: Cheilanthes sieberi subsp. sieberi
Synonyms: Cheilanthes humilis, Cheilanthes tenuifolia
Common name(s): Rock Fern

About:
A tough, drought-tolerant native fern adapted to dry rocky habitats throughout much of New Zealand. It forms upright clumps of finely divided fronds that remain attractive even in harsh exposed conditions. Unlike the closely related Woolly Cloak Fern, its fronds are largely hairless and lack the dense covering of scales and hairs.

Natural habitat:
Rock outcrops, cliff faces, rocky banks, dry bluffs, stony hillsides and exposed rocky ground with little surrounding vegetation.

Growing environment:
Prefers sunny, dry and free-draining sites. Thrives in rocky soils, crevices and exposed situations where moisture is limited and competition from other plants is low.

Endemic distribution:
Native to New Zealand but not endemic. Found throughout the Three Kings Islands, North Island and South Island. Also occurs in Australia and New Caledonia.

Height:
50–450 mm

Width:
100–300 mm

Flowering:
Does not flower (fern)

Fruiting:
Produces spores throughout the growing season.

Uses:
• Rock gardens
• Dry native gardens
• Pot culture
• Alpine houses
• Cliff and retaining wall plantings
• Restoration of rocky habitats

Appearance:

Growth habit:
A tufted terrestrial or rock-dwelling fern arising from a short creeping rhizome, producing dense clusters of stiff upright fronds.

Leaves:
Fronds narrow, erect and finely divided, up to 350 mm long. Stipes are red-brown to dark brown and mostly smooth, with only sparse hairs and scales. Leaflets are deeply divided with rolled margins and a smooth green surface.

Flowers:
None.

Fruit:
Spores are produced in elongated sori concealed beneath the rolled margins of the leaflets.

Ecology:
A characteristic fern of dry rocky environments where it survives prolonged drought and exposure. Minute spores are dispersed by wind, allowing the species to colonise cracks, crevices and bare rock surfaces.

Associated habitats:
Rock outcrops, dry cliffs, rocky grasslands, stony banks, bluffs, boulder fields and sparsely vegetated rocky slopes.

How to grow:
Plant in full sun or light shade in sharply draining soil. Ideal for rockeries, crevice gardens, stone walls and containers. Avoid waterlogged soils and excessive humidity.

Propagation:
Readily grown from spores. Plants often self-establish naturally in suitable rocky sites and can form long-lived colonies.

Cultural use:
A distinctive member of New Zealand’s dry-country fern flora and an important component of naturally rocky ecosystems.

Garden value:
An excellent low-maintenance fern for dry gardens where traditional ferns struggle. Its finely divided fronds and upright habit provide texture and contrast amongst rocks, gravel and drought-tolerant native plants.