In South Africa, the Prickly pear (Opuntia spp.) is now "planta non-grata," according to this Reuters report. Fed up with the spread of this South American native, which absorbs water from the soil of an already parched country, the government has developed a unique program that fights weeds and poverty at the same time. The program employs 20,000 temporary workers, who attack weeds with machetes and/or herbicide, and also mark plant positions using a GPS. An interesting note at the end of the article mentions another South American native, the Jacaranda tree (Jacaranda spp.), which can no longer be grown in the country. This species may get exemptions the Prickly pear could not, due to the Jacaranda's aesthetic value.