It is treated as an annual in Zone 8. It may have gotten too cold for it already.
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For instance, Duranta is hardy as a subtropical shrub or tree and develops into an irregular spreading large shrub or small tree 15 to 20 fe et tall in USDA zones 10 and 11. It serves as a 6 to 8 foot tall summer annual or shrubby perennial depending upon the severity of winter temperatures in zone 9, [b]or as a summer annual in zones 8 and colder[/b]. This is the case with other SuperStarTM plants such as Firebush (1990); 'Goldstar' Esperanza (1999); Plumbago (2005); and "Texas Lilac" Vitex (2005).