June 2011 Parkinsonia Parkinsonia aculeata
WHAT IS IT?
A prickly tree or large shrub that forms dense thickets of spiny vegetation One of four prickle bush weeds of concern in semi-arid Australia Native to southern United States of America to northern South America, but now a significant environmental weed in Queensland, Northern Territory and Western Australia. Has also been found in South Australia and New South Wales Also known as: Jerusalem thorn, Flowers at Naalae Rd Kula, Maui Feb. 09, 2001, Forest & Kim Starr Mexican palo verde, jelly bean tree, horse bean
Parkinsonia. “ Forest & Kim Starr” Plants of Hawaii. WHY IS IT A PROBLEM? If left untreated, forms impenetrable thickets on rangelands, particularly around water courses, preventing stock from accessing water, displacing native vegetation and hindering mustering Thickets shade out ground vegetation, and compete for water and nutrients Wetlands are vulnerable as thickets can dam watercourses, cause erosion, lower water tables and take over floodplains Infestations provide refuges for feral Thorny trunks: Forest & Kim Starr.
P. aculeata infestation. Image by – N.T. Govt. Thorny trunks. “Forest & Kim Starr,” animals, especially pigs www.nt.gov.au Plants of Hawaii.
What are State Alert Weeds? These are invasive weeds that are not known to be in South Australia, or if present, occur in low numbers in a restricted area, and are still capable of being eradicated. An Alert Weed would pose a serious threat to the State’s primary industries, natural environments or human health if it became established here. All Alert Weeds are declared under the Natural Resources Management Act 2004: their transport and sale are prohibited (Sect. 175 and 177), plants must be destroyed (Sect. 182), and if found on your land their presence must be notified to NRM authorities (Sect. 180) – refer overleaf.
DESCRIPTION A fast growing 2-8 m shrub or small tree with drooping leaves which have two sharp spines at the base of each leaf, that are arranged along zig-zagging branches. The branches have green bark enabling the plant to obtain sustenance even after complete defoliation from drought or grazing. Yellow 5-petalled flowers are arranged in loose clusters, and seeds are borne in straw-coloured pods which can float on water. HOW IT SPREADS Spread by seed, single mature plants can annually produce 5,000 or more seeds. These are carried large distances encased within pods that float downstream from infestations, or in mud attached to animals, footwear or machinery. Around 90% of seed that is dispersed is transported by water, especially floodwaters. HABITAT Found in tropical and sub-tropical along creeks, rivers, bores and dams in semi- arid regions, as well as grasslands, open woodlands, rangelands, pastures, disturbed sites and roadsides.
ORIGIN Parkinsonia thorns “Forest & Kim Starr”. Plants of Hawaii. Native to southern United States of America, the Carribean, northern Mexico, northern South America, and the Galapagos Islands.
DISTRIBUTION IN AUSTRALIA Current: Naturalised in central and northern parts of Northern Territory, coastal, central and western Queensland, and the Pilbara and Kimberley regions of Western Australia. Isolated populations have been recorded in South Australia and Western New South Wales.
Potential: Climate matching shows that Parkinsonia could be grown anywhere in South Australia, but it is chiefly a threat around watercourses and springs in the northern rangelands.
HOW IT GOT HERE DISTRIBUTION Used in ornamental plantings around homesteads and watercourses, such as hedging and shade trees, it was first introduced into Australia from Central Current distribution based on herbarium records America in the late 1800s. Currently used by some landholders to stabilise creek banks and add nitrogen to the soil. Potential distribution based on climate modelling WHAT CAN YOU DO? Be on the alert for this plant using this Fact Sheet as a guide. If you see a suspicious plant that may be this State Alert Weed, please report it to your local Natural Resources Management (NRM) Board (contact details at www.nrm.sa.gov.au). For more information on weeds, including Alerts, contact your local NRM Board or visit either www.pir.sa.gov.au/biosecurity (phone 08 8303 9620) or www.weeds.org.au.
Disclaimer: This publication is provided for the purpose of disseminating information relating to scientific and technical matters. The Government of South Australia does not accept liability for any loss and/or damage, including financial loss, resulting from the reliance upon any information, advice or recommendations contained in this publication. The contents of this publication should not necessarily be taken to represent the views of the participating organisations.