Johnson grass (Sorghum halepense)

Johnson grass is a clumping perennial grass up to 2 m tall. It invades cropping land and is a host of crop pests and diseases.

Profile

How does this weed affect you?

Johnson grass is a serious weed in most parts of the world. It is a summer growing perennial sorghum which grows up to two metres tall.

Johnson grass can be spread by seeds through contaminated hay, grain and seed and by rhizomes by cultivation and roadside grading. It invades cropping land, is a host of crop pests and diseases, is a contaminant of seed crops, is a safety hazard along roadsides and can be toxic to livestock.

What does it look like?

Johnson's grass is an erect perennial grass up to 2m tall. The leaves have a pronounced mid-vein and rough margins. The seedhead is 10-35 cm long, green to purplish, with loose spreading branches.

Where is it found?

Johnson's grass is widely distributed across NSW except for in the Western region.

It originates from the Mediterranean region.

Johnson grass grows in tropical, sub tropical and temperate climates. It is common in wet areas such as irrigated paddocks and crops, along waterways and roadsides. 

Maps and records

  • Recorded presence of Johnson grass during property inspections (Map: Biosecurity Information System - Weeds, 2017-2021)
    These records are made by authorised officers during property inspections under the Biosecurity Act 2015. Officers record the presence of priority weeds in their council area and provide this to the NSW Department of Primary Industries. Records reflect the presence of the weed on the date of inspection.

  • Estimated distribution of Johnson grass in NSW (Map: NSW Noxious Weed Local Control Authorities, 2010)
    Map shows weed distribution and density estimated by local council weeds officers in 2010.

More information

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Control

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.


Flupropanate 745 g/L (Tussock®)
Rate: 200 mL per 15 L of water
Comments: Knapsack spray.
Withholding period: Spot spray: Do NOT graze or cut for stock feed for at least 14 days. Blanket spray: Do NOT graze, or cut for stock feed for at least 4 months. If stock are grazed in treated areas after required time has passed, remove stock from treated areas and do NOT slaughter or milk for human consumption until they have been on clean feed for at least 14 days.
Herbicide group: J, Inhibitors of fat synthesis (Not ACCase inhibitors)
Resistance risk: Moderate


Flupropanate 745 g/L (Tussock®)
Rate: 1.0 L per 100 L of water
Comments: High volume spot spray.
Withholding period: Spot spray: Do NOT graze or cut for stock feed for at least 14 days. Blanket spray: Do NOT graze, or cut for stock feed for at least 4 months. If stock are grazed in treated areas after required time has passed, remove stock from treated areas and do NOT slaughter or milk for human consumption until they have been on clean feed for at least 14 days.
Herbicide group: J, Inhibitors of fat synthesis (Not ACCase inhibitors)
Resistance risk: Moderate


Flupropanate 745 g/L (Tussock®)
Rate: 12 L/ha
Comments: Boom spray.
Withholding period: Spot spray: Do NOT graze or cut for stock feed for at least 14 days. Blanket spray: Do NOT graze, or cut for stock feed for at least 4 months. If stock are grazed in treated areas after required time has passed, remove stock from treated areas and do NOT slaughter or milk for human consumption until they have been on clean feed for at least 14 days.
Herbicide group: J, Inhibitors of fat synthesis (Not ACCase inhibitors)
Resistance risk: Moderate


Glyphosate 360 g/L (Various products)
Rate: 1.0 L 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: 6.0 L/ha
Comments: Boom spray. Actively growing plants at early head stage.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate


Glyphosate 360 g/L (Various products)
Rate: 1.0 L glyphosate per 2 L of water
Comments: Wiper equipment.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate


Haloxyfop 520 g/L (Verdict® )
Rate: 200 - 400 mL/ha
Comments: Boom spray application
Withholding period: Do NOT graze or cut for stock food for 7 - 28 days after application. See label for more details.
Herbicide group: A, Inhibitors of fat synthesis (ACC'ase [acetyl coA carboxylase] inhibitors)
Resistance risk: High


Imazapyr 750 g/kg (Various products)
Rate: 2 kg/ha
Comments: Boom spray application
Withholding period: Do not graze or cut for stock feed.
Herbicide group: B, Inhibitors of acetolactate synthase (ALS inhibitors)
Resistance risk: High


MSMA 720 g/L (Armada 720 SL)
Rate: 1.1 L per 100 L of water
Comments: Spot spraying.
Withholding period: 5 weeks.
Herbicide group: Z, Herbicides with unknown and probably diverse sites of action
Resistance risk: Moderate


MSMA 720 g/L (Armada 720 SL)
Rate: 11–13.3 L/ha in 500 L of water
Comments: Boom spraying.
Withholding period: 5 weeks.
Herbicide group: Z, Herbicides with unknown and probably diverse sites of action
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.
Central West Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. Land managers should mitigate spread from their land. The plant should not be bought, sold, grown, carried or released into the environment.
*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfil the general biosecurity duty for this weed click here

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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 2017