Blue Vervain 4 oz by Herb PharmWe prepare our Blue Vervain Extract from the flowering tops of Verbena hastata & lasiostachys plants which are Certified Organically Grown on our own farm and or Custom Wildcrafted in their natural wild habitat. To assure optimal extraction of Blue Vervain's bioactive compounds, the uppermost tops of the plants are hand harvested only when in full flower, are carefully shade dried to retain their full color & aroma, and are then thoroughly extracted.