Distribution

More info for the terms: cover, natural, reclamation

Thorny-olive is not native to the United States but was introduced from Asia in 1830 [15,22]. As of 2011, escaped populations were suspected nearly throughout the southeastern United States from Kentucky and Virginia south to Louisiana and Florida [37]. Thorny-olive may also occur in natural areas of Massachusetts and Washington DC [54]. Plants Database provides a map of thorny-olive's US distribution.

Since its introduction as an ornamental, thorny-olive has frequently been planted in hedgerows and along highways [15,37,57]. It has also been used to revegetate mine sites [41,50]. Because thorny-olive grows densely even in harsh conditions, it was "extensively" planted in highway medians in the Southeast. As of 2000, the Virginia Department of Transportation had been planting thorny-olive along roadways for about 20 years [57]. Thorny-olive was also used in highway medians in Texas [16]. Around 1970 in eastern Kentucky, thorny-olive was planted on surface mine spoils and because establishment was successful and surival high, it was recommended for further use in mine reclamation [41]. On a coal surface-mined area in Laurel County, Kentucky, thorny-olive was still present and described as growing well or increasing 18 years after planting [50].

Reports on the extent of invasive populations of thorny-olive in the United States were rare, although surveys provided cover estimates in southern forests and indicated US range expansions. Forest Inventory Analysis data from 12 southern states in 2008 indicated that thorny-olive occupied an estimated 6,107 acres (2,471 ha) in forests in 6 states. It was most widespread in forests of Georgia (3,380 acres (1,368 ha)) and South Carolina (about 2,000 acres (800 ha)) [38]. In Florida, thorny-olive was known outside of cultivation only in the panhandle until about 2000, when it was reported in Alachua and Marion counties [28]. In 2003, it was reported as an escape in St Lucie County, 160 miles (250 km) south of Marion County [39]. In 1997, thorny-olive was reported as infrequent but spreading on the barrier islands of northern North Carolina [47].