Weeds

Fishbone fern – Nephrolepis cordifolia

Fishbone fern is an Australian native plant endemic to the northern and central coasts of New South Wales. It has become invasive as an environmental weed in areas around Sydney.

This is a native plant. Check native vegetation requirements before undertaking control

Profile

Family

Davalliaceae (New South Wales, Victoria, Western Australia and the Northern Territory)
Nephrolepidaceae (Queensland)

Common Names

Erect sword fern, fishbone fern, herringbone fern, ladder fern, narrow swordfern, southern sword fern, sword fern, tuber fern, tuberous sword fern.

Origin

The exact native range of this species is obscure, partly because it has often been confused with other similar species. It is thought to be native to many tropical regions of the world (i.e. pan-tropical), including some parts of northern Australia (i.e. the coastal districts of eastern Queensland and some parts of north-eastern New South Wales).

Cultivation

This species is widely and commonly cultivated in gardens and amenity areas, particularly in eastern and southern Australia.

Naturalised Distribution

Naturalised in Victoria, in the coastal districts of south-western Western Australia, on Norfolk Island and beyond its native range in the coastal districts of central New South Wales. Possibly also naturalised on Lord Howe Island and regarded as being naturalised in some habitats and areas that are outside its natural distribution in south-eastern Queensland and north-eastern New South Wales.

Widely naturalised overseas in Africa, temperate Asia, New Zealand and south-eastern USA (i.e. Florida, Alabama and Georgia).

Habitat

In its natural environment, fishbone fern (Nephrolepis cordifolia) is usually found growing in rocky areas, on rainforest margins, or as an epiphyte on palm trees in the wetter parts of tropical and sub-tropical Australia.

It is mainly a weed of parks, gardens, roadsides, fence lines, disturbed sites, waste areas, railway lines, suburban bushland, riparian areas and coastal environs in sub-tropical and warmer temperate regions.

Habit

A fern with upright (i.e. erect) or drooping fronds usually growing about 50 cm tall, but occasionally reaching up to 1 m in height.

Distinguishing Features

a fern with upright or drooping fronds usually up to 50 cm long.
this species often produces distinctive round tubers on its creeping underground stems.
its ‘leaves’ are divided into numerous alternatively arranged narrow ‘leaflets’ (10-35 mm long and 4-11 mm wide).
the lower parts of the ‘leaflets’ are usually somewhat overlapped and slightly lobed on one side, while their tips are relatively broad and somewhat rounded.
its brown spores are produced is small clusters midway between the centre and the margin of the undersides of the ‘leaflets’.

Stems and Leaves

It forms a network of creeping stems (i.e. rhizomes and/or stolons) and usually develops some fleshy rounded (i.e. spherical) tubers (about 15 mm across). The creeping stems (i.e. rhizomes and stolons) and lower parts of the ‘leaves’ (i.e. stipes) are densely covered in glossy brown elongated (i.e. linear-lanceolate) scales.

Its upright ‘leaves’ (i.e. fronds) have a brownish-coloured stalk (i.e. stipe) up to 15 cm long and are divided into numerous alternatively arranged narrow ‘leaflets’ (i.e. pinnae). These ‘leaflets’ (usually 10-35 mm long and 4-11 mm wide, but rarely to 6 cm long) have irregularly and often finely scalloped (i.e. crenate or crenulate) margins and are usually hairless (i.e. glabrous). Their tips (i.e. apices) are relatively broad and somewhat rounded (i.e. obtuse) and their bases are usually somewhat overlapping and slightly lobed on one side. Fronds tend to be dull green in shaded areas and lighter green or yellowish-green when growing in a sunny position.

Flowers and Fruit

Numerous brown, round to kidney-shaped (i.e. reniform), spots will be evident on the undersides of mature fronds. These are the reproductive structures of this species (i.e. sori) and contain the numerous spores. They are partially protected by a tiny kidney-shaped flap of ‘leaf’ tissue (i.e. a reniform indusium). These reproductive structures (i.e. sori) are arranged in two rows on the undersides of the ‘leaflets’ (i.e. pinnae), each row being midway between the margin and the centre (i.e. midrib).

Reproduction and Dispersal

This species reproduces by spores and vegetatively via underground stems (i.e. rhizomes) and often also by fleshy underground tubers.

Spores are most commonly spread by wind and water, while the rhizomes, tubers and spores are most often dispersed to new areas in dumped garden waste.

Environmental Impact

Fishbone fern (Nephrolepis cordifolia) is regarded as an environmental weed in New South Wales and Queensland.

Legislation

Not declared or considered noxious by any state government authorities.

Control

Hand pulling or digging. Bagging all plant parts and removing from site.

Similar natives that are not weeds

An introduced species, invasive or non-native species is a species living outside its native distributional range, but which has arrived there by human activity, either deliberate or accidental. These organisms have often been introduced to areas in which they are not native, usually without much regard to the harm that could result.

In many cases there are native plant species that resemble the introduced variety. If you like the look of the introduced species, why not consider an Australian native species with similar aesthetics instead. You will not only have a beautiful garden, you will also be doing something positive for the local flora and fauna.

Prickly Rasp fern (Doodia aspera)

Doodia aspera, commonly known as the Prickly Rasp Fern. This fern is found growing in a variety of habitats such as rainforest margins, eucalypt forests and rainforests. It is well adapted to both sunny and shaded areas. The fern occurs in Queensland, eastern New South Wales, and eastern Victoria.

D. aspera is a terrestrial fern producing short-creeping rhizomes and erect fronds. The fern can reach height to 35 cm. Its rhizome is small and covered with black scales. The fertile and sterile fronds are similar in appearance. The fronds are 0.15 – 0.4 m tall and are ovate to lanceolate in shape. The new growth fronds are bright pink but old ones are green. This feature makes the fern an attractive plant for garden culture.

The fern is usually easy to grow in gardens, containers and baskets. Having a spreading growth habit makes D. aspera suitable as a groundcover. It grows best in shady conditions and in acidic soil, with high organic composition. Although the plants like a good level of moisture, the plants need well-drained conditions to prevent sweating problems.