Johnson Grass

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Sorghum halepense


This is a slender plant with numerous erect stems that grow up to 2 metres high.

Leaves are long, narrow and smooth, growing to 30 to 60 centimetres long and 2 centimetres wide. They have a prominent white midvein and hairs at the base of the upper surface; otherwise the leaves remain smooth and hairless. They are arranged on alternate areas of the stem.

Flower heads are often purple in colour, 25 to 45 centimetres long and 3 to 15 centimetres wide which open when mature. Little spikes are located in pairs or threes along the branches.

Seeds are usually dark brown or black when mature.

Habitat it is found on agricultural land, road sides, disturbed and wet areas, railway easements and canal banks.

Weed characteristics it can spread rapidly onto cultivated lands. It can be toxic to livestock especially during periods of new growth. It is difficult to control. It can cross-pollinate with other sorghums, causing seed contamination.

Dispersal it spreads by wind, vehicles/machinery and animals.

Declaration Details

This species is not a declared plant under Queensland legislation although its control is recommended.

How to act

This plant can be controlled by spot spraying with an appropriate herbicide. Painting the leaf blades with a wiper covered in chemical-soaked wick or carpet may be an effective treatment if growth rates are appropriate.

Refer to Weed Control Methods.


Related information

Johnson Grass © NQ Dry Tropics 2011
Johnson Grass © NQ Dry Tropics 2011

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