NQ DRY TROPICS WEED FREE pg . 49
JOHNSON GRASS
Sorghum halepense
DESCRIPTION
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 .
BIOSECURITY MATTER
This species is not listed under Queensland Legislation however it may be listed under local government law and control is highly 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 .
GRASSES JOHNSON GRASS