(Eupatorium) These hardy and frost tender perennials and shrubs are found in North and South America, Europe and Asia and are grown mainly for their flowers, though some are valued for their ornamental foliage. The name commemorates Mithridates Eupator, King of Pontus, who is credited with discovering that one of the varieties could be used as a re... Found on http://www.encyclo.co.uk/local/10004