[gobotany.nativeplanttrust.org] South America native, invasiveness: Clasping heliotrope is an invasive weed originating in South America, and present in the southeast United States plus Texas and California. It is not often seen in New England, having been collected only in Massachusetts in disturbed areas and gardens. This plant is sometimes grown as an ornamental, and is considered a serious weed in some parts of the world, as it invades pastureland and is highly poisonous to cattle. (link added by Mary Ann Machi)