The Mexican Palo Verde (Parkinsonia aculeata) is an invasive species in many parts of the world, but it is open to debate whether it is native to southern Arizona. It very well may be a native from southern Arizona and Sonora and is not serious concern as an invasive in our region. It does fare well in disturbed areas, but does not substantially replace native trees in southern Arizona.
"Jerusalem thorn (Parkinsonia aculeata) is a shrubby, thorny tree, similar to kiawe (Prosopis pallida). Jerusalem thorn is widely cultivated and is known to spread from initial plantings in North America, as far north as California, Arizona, and Florida, the West Indies, Australia, Hawai'i, and Micronesia (DNR 1998; PIER 2000; Wagner et al. 1999). In Australia, it forms impenetrable thickets along water courses and seeds spread downstream to cause further infestations. On Maui, Parkinsonia has been known from only three sites, none of which no longer exist. The potential range on Maui is suspected to be much more than its current range, possibly wherever Prosopis exists. Eradication of this species now and further exclusion from Maui could potentially save time and money of controlling infestations in the future."
