Burr ragweed (Ambrosia confertiflora)

Profile

Impact

Burr ragweed is not palatable to stock and by forming dense stands which exclude all other plants can reduce carrying capacity. The burrs cause vegetable fault in wool and are not easily removed because of the hooked hairs. It produces large amounts of allergenic pollen which can cause hay fever.

Distribution

Burr ragweed was introduced from the southern USA and Mexico. Burr ragweed infests areas of south-east Queensland and the western slopes and plains of NSW.

Description

Burr ragweed is a perennial herb growing to 2 m high. Leaves are large up to 16 cm long and 10-15 cm wide, they are deeply divided.

Plants die back to the roots over winter but grow rapidly in spring and summer and flower in mid-summer. If dry spells occur in summer plants may die back and resprout in autumn.

Burrs form in clusters with short, stout, hooked spines.

References

Auld BA and Medd RW (1999). Weeds. An illustrated botanical guide to the weeds of Australia. Inkata Press, Melbourne.

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Control

Herbicide options

Contact your local council weeds officer for control advice for Burr ragweed (Ambrosia confertiflora).

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Biosecurity duty

The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.

Area Duty
All of NSW General Biosecurity Duty
All plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable.
Central Tablelands Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
Central West Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment.
Western Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfill the general biosecurity duty for this weed click here

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Reviewed 2017