Spiny emex (Rumex hypogaeus)

Also known as: cathead, doublegee, prickly jacks, three-cornered jacks

Spiny emex is a low growing annual herb with spiny woody fruit. It is a weed in crops and pastures.


How does this weed affect you?

Spiny emex is a serious weed of crops and pastures.

Livestock health

Spiny emex contains oxalates in the leaves which are toxic to ruminants especially sheep.

The spiny fruit can cause lameness in livestock.

What does it look like?

Spiny emex is a low growing annual herb. It has fleshy stems up to 80 cm long and 40 cm high that grow from the centre of a rosette.

Leaves are 3–9 cm long and 1.5–7.0 cm wide on a stalk 2- 10 cm long. The leaf margins are sometimes finely toothed. 

The brown, woody fruit have a pyramid-like shape and three spines . They are 9–13 mm wide. There is only one seed per fruit. They are glossy brown. 

Scientific name change

This plant was previously named Emex australis.

Where is it found?

Spiny emex grows in all parts of NSW except the northern and southern tablelands and the far south coast. It grows mainly on lighter sandy soils but can thrive on heavier soils that retain water.

Spiny emex is native to South Africa.

How does it spread?

Spiny Emex spreads by seed. The spines on the fruit attach to shoes, tyres, and the feet of animals. The fruit can float and are spread in waterways and flood waters. 

It is also spread in contaminated produce including lucerne hay, clover seed and feed wheat.

More information

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Biological control

A weevil (Perapion neofallax) was released and has become established at a few sites, but it has had no impact on controlling spiny emex. 

Herbicide options

Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au

See Using herbicides for more information.

2,4-D 300 g/L + Picloram 75 g/L (Tordon® 75-D)
Rate: 300 mL per 100 L of water
Comments: Spot spray. For use in grass pastures.
Withholding period: Do not graze or cut crops (except sugar cane 8 weeks) or pastures for stock food for 7 days after application.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

Glyphosate 360 g/L (Various products)
Rate: 500–700 mL per 100 L of water
Comments: Spot spray.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate

Glyphosate 360 g/L (Various products)
Rate: 2.0–3.0 L/ha
Comments: Boom spray. Young, actively growing plants.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate

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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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For technical advice and assistance with identification please contact your local council weeds officer.

Reviewed 2014