Christella, Soft Fern

Botanical name: Christella dentata
Synonyms: Polypodium dentatum; Dryopteris dentata; Thelypteris dentata; Cyclosorus dentatus; Polypodium nymphale
Common name(s): Christella, Soft Fern

About:
A soft, graceful fern with pale green, finely divided fronds arising from a creeping rhizome. Native to northern New Zealand and widespread throughout tropical and subtropical regions of the world, it is valued for its lush appearance and ability to colonise damp, disturbed habitats. The fronds are velvety to the touch and wilt readily when broken, giving the plant a delicate appearance despite its vigorous growth.

Natural habitat:
Coastal wetlands, riverbanks, alluvial forest remnants and other moist, frost-free habitats. It commonly grows in disturbed ground and forest margins and is abundant on Raoul Island in the Kermadec Islands.

Growing environment:
Prefers warm, sheltered positions with moist, fertile soil and partial shade. Thrives in humid environments and tolerates a wide range of soil types provided moisture is available. Frost sensitive.

Endemic distribution:
Not endemic. Indigenous to New Zealand and widespread throughout tropical and subtropical regions of the world. In New Zealand it occurs naturally on Raoul Island and in the far north of the North Island.

Height:
0.5–2 m

Width:
1–3 m, spreading by creeping rhizomes

Flowering:
Does not flower. Spores produced throughout the year.

Fruiting:
Spores may be present year-round.

Uses:
• Fern gardens
• Wetland and streamside plantings
• Tropical and subtropical gardens
• Underplanting beneath trees
• Ground cover in shaded areas
• Habitat restoration in frost-free regions

Appearance:

Growth habit:
A softly textured fern forming spreading colonies from a stout creeping rhizome. Fronds arise in numerous tufts and create a lush, arching mass of foliage.

Leaves:
Fronds are broadly ovate to oblong, pale to yellow-green and softly hairy throughout. They are pinnate with oblong to lance-shaped pinnae that become smaller toward the frond tips. Secondary pinnae are deeply lobed with rounded ends.

Spores:
Small circular sori occur in rows on the underside of the frond lobes. Each sorus is covered by a heart- to kidney-shaped indusium.

Ecology:
Spores are dispersed by wind and water. The species is a pioneer fern of disturbed habitats and can spread rapidly in suitable environments. In New Zealand two distinct forms occur: a widely creeping form and a more upright “geothermal race” associated mainly with geothermal areas.

Associated habitats:
Coastal wetlands, river margins, alluvial forests, forest clearings, geothermal areas and disturbed ground.

How to grow:
Plant in moist, fertile soil in partial shade or filtered light. Protect from frost and drying winds. Water regularly during dry periods and maintain consistent soil moisture. In warm gardens it may naturalise readily.

Propagation:
Easily propagated by division of established clumps or from spores. Rhizome divisions establish quickly under warm, moist conditions.

Cultural use:
Although not widely recorded in Māori tradition, this fern has been used elsewhere as an edible plant and in traditional medicine. It is an attractive and adaptable fern valued for its soft texture and tropical appearance.

Garden value:
An elegant fern ideal for creating a lush, tropical effect in sheltered gardens. Its soft foliage and vigorous spreading habit make it an excellent choice for wetland plantings, shaded borders and subtropical landscapes.