What does it look like?
Bathurst bur is a spiny plant that grows up to 1m tall; it has well-branched upright stems with triple spines grouped in opposite pairs. The leaves are three-pronged, narrow and pointed with a white midrib above and a whitish colour on the underside. Bathurst bur has inconspicuous flowers, and the fruit are bur-like with hooked spines.
Bathurst bur can adapt to a wide range of climatic conditions, although it prefers moist soil, as it needs plenty of water. It’s usually found on fertile, disturbed or bare ground, particularly in pasture and cultivated areas.
Why is it a problem?
Bathurst bur is a highly invasive weed and can quickly dominate large areas, out-competing crops, forage plants and native flora. It spreads entirely by seeds, which are within the spiny burs. Seed may lie dormant for many years before germinating, forming a very long-lived seed bank. In pastoral settings, it can affect wool value with the burs getting tangled in wool. Seedlings when very small are toxic to stock.
Control methods
Physical control
Grub out plants before flowering (March to April).
Herbicide control
Spray before plants set seed with 1g metsulfuron + 20ml penetrant per 10L water. Or 120ml Tordon Max per 10L water. Or 100ml glyphosate per 10L water.
Avoid soil disturbance and bare ground. Maintain good pasture cover to prevent re-establishment. Replant with native species where appropriate.
CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.
More information
Bathurst bur is listed as a Sustained Control pest in the Hawkes Bay Regional Council Regional Pest Management Plan 2018 – 2038 and is subject to Plan Rule 18.
It is an offence to distribute, breed or sell Bathurst bur in accordance with Section 52 and 53 of the Biosecurity Act.
Related links
http://www.nzpcn.org.nz/flora_details.aspx?ID=2651
http://www.nzflora.info/factsheet/Taxon/Xanthium-spinosum.html
Management Programme
Sustained Control Programme
To provide for ongoing control of the subject, or an organism being spread by the subject, to reduce its impacts on values and spread to other properties.
Unwanted Organism
An unwanted organism is any organism that's capable of causing harm to natural or physical resources (like forests and waterways) or human health. A number of introduced pests in New Zealand are classed as unwanted.
Rules
Plan rule 18 - Bathurst bur and variegated thistle plants
All occupiers shall, on receipt of a written direction from an Authorised Person, destroy all [NAME] plants within 5 metres of the property boundary, or on land that they occupy where an adjoining occupier is also destroying or the land is clear of, all plants within 5 metres of the property boundary. Council will administer the rule upon receiving a written complaint from the adjacent land occupier and/or at the discretion of the Authorised Person.
Taxonomies
FamilyAsteraceae
TypePlants
GroupGroundcover
HabitatLand
Management ProgrammeSustained Control ProgrammeUnwanted Organism
RulesPlan rule 18 - Bathurst bur and variegated thistle plants
