Fishbone fern (Nephrolepis cordifolia)

Fishbone fern is an Australian native plant that has a natural range from north east Queensland to north east NSW. It is an invasive weed in some parts of NSW.

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How does this weed affect you?

Fishbone fern is an Australian native plant endemic to the northern and central coasts of New South Wales. It has become an invasive weed in other bushland areas. It chokes out other low growing plants and stops other native plants from growing.

What does it look like?

Fishbone fern has upright or drooping fronds and is about 50-75 cm tall.  Plants grow in thick clumps. Above ground stems (stolons) creep along the ground and can form dense mats.

Fronds (leaves) are:

• dull or lime-green
• upright or drooping with rounded tips and wavy edges
• up to 75 cm long and 5-8 cm wide
• divided into many smaller pinnae (leaflets) uo to 6 cm long, alternate along central stalk (look like a fish skeleton).

Spores:

Spores are the reproductive part of ferns. They are contained in structures called sori, which are brown spots that grow in rows underneath the fronds. The sori are in rows halfway between the midvein and the margin of each pinnae.

Stems and roots:

Fishbone fern has a creeping network of rhizomes and stolons that can cover the ground.

Rhizomes are:

• underground stems that grow in the soil 
• covered with brown scales 
• often have a small (15 mm) fleshy, round tuber attached.

Stolons (runners) are:

• thin stems that run horizontally along the ground
• slender and wiry
• also have some scales.

Similar looking plants

Fishbone fern looks like other native ferns, including:

• sickle ferns (Pellaea species) and water ferns (Blechnum species), which have spores in a continuous line around leaf edges (instead of a row of separate dots)
• rasp ferns (Doodia species), which feel rough and sandpapery and have leaflets with jagged edges and pointy tips.

They can also be confused with Boston fern (Nephrolepis exaltata), an introduced garden plant. Boston fern does not have tubers on the rhizomes and sori are covered with a round tissue flap.

Where is it found?

Fishbone fern is an Australian native plant that occurs naturally from north east Queensland to north east New South Wales.

It has become an invasive weed in areas around Sydney, coastal districts of central New South Wales and Lord Howe Island. It is also weedy in parts of Queensland and Victoria. 

What type of environment does it grow in?

Fishbone fern grows in moist, rocky areas; rainforests and in trees in its native range. It has become weedy:

• in urban bushland
• in disturbed areas such as roadsides
• along waterways
• in parks and gardens.

How does it spread?

Fishbone fern can spread by spores or plant parts. Spores are spread by:

• wind
• water
• contaminated soil, including through earthworks, shoes and tyres.

Plants also spread through rhizomes, when garden waste is dumped.

More information

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Control

Fishbone fern is a native plant. Control may not be appropriate in some areas with native vegetation.

If control is required it can be hand pulled, dug up or sprayed with herbicides.

Control can be difficult and time consuming because:

• it has a hardy root system 
• plants don’t respond well to herbicides.

Sites should be revisited and several control attempts may be needed.

Physical removal

Manual removal of isolated, small seedlings can be attempted by hand pulling or digging them up. This is only practical for a small number of plants.

It is important to remove the whole root system if possible, otherwise the plant can regrow. 

Chemical control

Fishbone fern can be spot sprayed. Plants are often hard to kill with herbicides so follow up with inspections and re-treat if necessary.

Herbicide options

See Using herbicides for more information.

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PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L with Metsulfuron-methyl 600 g/kg (Various products)
Rate: 200 mL glyphosate plus 1.5 g metsulfuron-methyl per 10 L of water
Comments: Knapsack spot spray.
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

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PERMIT 9907 Expires 31/03/2025
Metsulfuron-methyl 600 g/kg (Various products)
Rate: 1.0–2.0 g metsulfuron-methyl per 10 L of water
Comments: Knapsack spot spray.
Withholding period: Nil (recommended not to graze for 7 days before treatment and for 7 days after treatment to allow adequate chemical uptake in target weeds).
Herbicide group: 2 (previously group B), Inhibition of acetolactate and/or acetohydroxyacid synthase (ALS, AHAS inhibitors)
Resistance risk: High

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Biosecurity duty

The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.

Area	Duty
All of NSW	General Biosecurity Duty All pest plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable.

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Reviewed 2020