Pest plant - Bathurst Burr
Bathurst burr (
) is a spiny annual weed. Successful control requires treatment of seedlings and the following germinations. It is important to keep Bathurst burr off clean properties or to recognise and destroy new infestations before they become established.
erect, densely branched annual herb to 1m high
leaves are dark green and shiny on upper side, underside is pale green and downy
leaves are 7cm long and usually have 3 lobes, at the base are 3-pronged yellow spines, 1.5-2.5cm long
flowers are small, creamy-green, at the end of stems and also at leaf nodes
the burr is straw coloured and oblong in shape, 1-1.5cm long and 4-5mm wide, covered with hooked spines
each burr contains two seeds that are flat, black and 1cm long
plant has a branched taproot.
Why is it a problem?
burrs of this plant contaminate wool, adding to the cost of handling and processing, as well as to the final cost of the woollen product
spines of this plant cause physical damage to stock, people and shearing machinery
competes strongly with summer crops and is host for horticultural diseases
seedlings are poisonous to most stock animals (the toxin is hydroquinone).
Eyre Peninsula – isolated plants, especially after rain
Northern pastoral – very common but decreasing further north
Northern agricultural districts and Yorke Peninsula – widespread
Murray Mallee – scattered infestations
South East - scattered with some large infestations
Central region – scattered
prefers highly fertile disturbed soil, often found near watercourses, dams and flood plains
staggered germinations occur after late spring and summer rains, or irrigation
grows quickly in warm weather, burrs are formed in February and continue for several months
newly germinated plants can produce burrs at a few weeks of age
most plants die in early winter
seeds can germinate out of season and mature plants can be found at any time of year.
How it spreads
by animal movement, the hooked spines on the burrs cling to wool and fur
burrs are also easily carried on clothing, packaging and water, and may contaminate summer crops.
Pest plants (web page)