familySubfamily Caesalpinsoidae within Fabaceae (peas)
statusParkinsonia or Jerusalem thorn (Parkinsonia aculeata) is listed as noxious in in category 2 (a notifiable weed: the local control authority (local council) must be informed if you see this weed, and it must be eradicated and the land must be kept free of the weed) in Southern Slopes and Upper Lachlan LCAs within the Southern Tablelands and South East Region. It is illegal to sell, propagate or knowingly distribute this species anywhere in NSW. It is also listed as a Weed of National Significance.
DescriptionParkinsonia is a straggling shrub or small tree to 8 metres high with drooping zigzag branches. Leaves are bipinnate, similar to those of wattles, but with a broad flat central rib to which 10-40 pairs of small (4-7mm long) oval leaflets are attached. Flowers are yellow and poinciana-like, in long, open terminal spikes. There are four yellow petals and one orange or orange-spotted petal. The pods are cylindrical and bean-like. There is a single spiny thorn 3-15mm long at the base of each leaf. The photos of this species were provided by Forest & Kim Starr, USGS, Hawaii.
View the fact sheet on this weed at the link below.
Preferred habitat and impacts
Parkinsonia has naturalised from garden and soil stabilisation plantings in the arid inland and sub-humid tropics, including western NSW, and has invaded arid pasture land, particularly along watercourses.
It reduces carrying capacity, restricts access to water, and creates difficulty with mustering stock. It also replaces native vegetation, reducing habitat for native animals, and providing harbour for feral animals such as pigs and goats.
DispersalParkinsonia could escape into new areas of infestation from garden or farm plantings. The pods and seeds float in water and may be spread in mud on animals, vehicles and machinery. The pods are not palatable so animal droppings are not very likely as a means of spread for this species.
Mesquite (Prosopis species), also noxious in NSW and a Weed of National Significance, is the most similar species. See the entry for that weed for a description and images of it and the following look-alikes: black locust (Robinia pseudoacacia) and honey locust (Gleditsia triacanthos), also in the pea family are also thorny trees. Both these weedy trees sucker from the roots to form thickets and spread by the same means as mesquite and parkinsonia.
ControlDo not plant parkinsonia and if you see if being offered for sale anywhere, inform your local Council weeds staff. If you have parkinsonia planted it would be advisable to remove them. Cutting the tree down and painting the stump with glyphosate would probably be the most efficient way to do this, although follow-up cutting and painting may be needed to deal with regrowth suckers arising from the root system.