Asplenium australasicum (Bird's nest fern)

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Asplenium, Genus, australasicum, Species,

Genus & species

Bird's nest fern

Aspleniaceae

Eastern Australia and southwestern Pacific

Container Friendly

SunPart Shade – Full Shade

WaterMedium

HardinessZones 10–12

Overview

Asplenium australasicum is a large epiphytic fern from the rainforests of eastern Australia and nearby Pacific regions, where it perches on tree trunks and rocks rather than rooting in the ground. It forms a broad rosette of undivided, strap-like fronds 3-7 feet (1-2 m) long that radiate from a central crown, building a nest-like hollow that traps falling leaves and water. The fronds are glossy bright green, leathery, and slightly wavy at the margins, with a prominent dark midrib that is angled or keeled beneath, a feature that separates it from the similar Asplenium nidus. Reproduction is by spores carried in long brown lines on the underside of mature fronds, so the plant never flowers. Litter caught in the central nest breaks down to feed the fern, an adaptation to life high on tree branches with little soil. It grows in warm, humid, shaded conditions and is frost-tender, which limits outdoor use to mild and tropical climates. Old fronds brown and collapse from the outer edge of the rosette and can be removed as they age.

Native Range

Native to eastern Australia, mainly Queensland and New South Wales, and extending to islands of the southwestern Pacific. It grows as an epiphyte on rainforest trees and as a lithophyte on rocks in warm, humid, shaded forest.

Suggested Uses

Asplenium australasicum is used as a feature foliage plant in shaded tropical and subtropical gardens, mounted on trees, or grown in pots and hanging baskets. Indoors and in conservatories it is grown for its broad evergreen rosette in low to moderate light. It suits fernhouses, courtyards, and shaded patios in frost-free areas.

How to Identify

Recognised by its broad rosette of undivided, strap-like glossy green fronds forming a central nest, and by the dark, raised midrib that is keeled on the underside of each frond. Long brown lines of spore cases run outward from the midrib on fertile fronds. The keeled midrib separates it from Asplenium nidus, whose midrib is rounded beneath.

Appearance

Size & Dimensions

Height3' - 7'

Width/Spread3' - 5'

Colors

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Ferns do not flower; Asplenium australasicum reproduces by spores. Brown linear spore cases form on the undersides of mature fronds, mainly through the warmer months. Wind-borne spores are released when ripe.

Detailed Descriptions

Foliage Description

Glossy bright green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Requires 1-4 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.0 - 6.5 (Acidic to neutral)

3579

Soil Types

peat loam

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

tender

Care & Maintenance

Care Guide

Asplenium australasicum grows in shade to part shade in warm, humid, frost-free conditions, either mounted on a tree or rock or potted in a coarse, free-draining mix rich in organic matter. Water can be directed into the central nest as well as around the roots, keeping the medium moist but never waterlogged. Hot direct sun scorches the fronds, and cold below about 40 F (5 C) kills exposed plants. Indoors it suits a bright, draught-free spot away from heaters. Feeding is light, with dilute liquid fertiliser in the warmer months. Dead outer fronds can be trimmed to keep the rosette tidy.

Pruning

Pruning is limited to removing old, browned fronds from the outer edge of the rosette as they die back. The growing centre of the nest is left untouched, as damage there can kill the plant. Fronds are cut close to the base with a clean blade.