Mintweed (Salvia reflexa)

Mintweed is a small grey-green plant with multiple branches and square stems. It is toxic to livestock.

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How does this weed affect you?

Mintweed infests summer crops and pastures. It is toxic but seldom eaten by livestock. Travelling stock, young stock and hungry stock are most at risk.

What does it look like?

Mintweed is a branched erect annual herb up to 70 cm high but often less than 15 cm tall. It has a blue-green appearance and emits a strong mint aroma when crushed. The stems are square and often covered in short hairs.

Leaves are blueish green, in opposite pairs, 1.5–5 cm long and 0.4–1.2 cm wide and have shallow teeth along the margins. The flowers are tubular, pale blue and up to 1.2 cm long. The fruit are a capsule with 4 seeds.

Where is it found?

Mintweed grows in many regions of NSW especially in areas with fertile clay soils. It is a weed in crops, pastures, roadsides and waste places.

Mintweed is native of North & South America. 

How does it spread?

It is thought to have been introduced to Australia in hay in the early 1900's.

Mintweed is spread by seed, which can be transported by water runoff, mud which adheres to animals, humans or machinery or as a contaminant of agricultural produce or seed. Mintweed grows rapidly and sets seed within 2 months of germination. 

References

Parsons, W.T., & Cuthbertson, E. G. (2001). Noxious weeds of Australia. CSIRO publishing.

PlantNET (The NSW Plant Information Network System). Royal Botanic Gardens and Domain Trust, Sydney. Retrieved 11 May 2020 from: https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Salvia~reflexa

More information

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Control

Mintweed can be supressed by maintaining vigorous perennial pastures. If possible apply herbicides before plants set seed.

Herbicide options

WARNING - ALWAYS READ THE LABEL
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 amine 625 g/L (Amicide® 625)
Rate: 1.1 L/ha
Comments: Boom spray application
Withholding period: 7 days.
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: High volume 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. Apply to actively growing plants.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate


MCPA 500 g/L (Various products)
Rate: 2.0 L/ha
Comments: Boom spray application for actively growing seedlings.
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
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 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.
For further information call the NSW DPI Biosecurity Helpline on 1800 680 244 or send an email to weeds@dpi.nsw.gov.au

Reviewed 2020