Xanthium strumarium (syn occidentale and pungens)
This is an annual branched herb that grows to 2.5 metres high.
Stems are purple tinged and rough to touch.
Leaves are roughly textured, dark green with purple veins, growing to about 15 centimetres wide with minute bristles. There are 3 to 5 large lobes. The lower leaves are arranged opposite each other on the stem and the upper leaves are arranged on alternate areas of the stem.
Flowers occur in the leaf axils towards the end of the branches. It flowers all year round.
Seeds are brown hairy burrs about 2 to 3 centimetres long. They have spines at the end containing 2 seeds in separate compartments.
Habitat it is found along river and creek flats, on roadsides and in pasture land following seasonal rain or floods.
Weed characteristics seeds are poisonous to stock and the burrs contaminate wool.
Dispersal is by seeds in burrs which attach to animals, clothing and bags.
This species is not a declared plant under Queensland legislation although its control is recommended.
How to act
Foliar spraying of this weed is very effective as it is an annual plant it can be treated before it seeds. Hand pulling or mechanical control of small or isolated plants can also be conducted before flowering.
Refer to Weed Control Methods.
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