Seeds from this Codonopsis clematidea or Bonnet Bellflower . This herbaceous perennial, commonly referred to as a vine, with its vining tendencies and 2 to 3 feet height, looks more like a perennial; however, it does twine like a vine. Native to the rocky mountain slopes of East Asia, the name Codonopsis comes from the Greek word kodon, meaning a bell and opsis, referring to the bell-shaped flower. Clematidea refers to its clematis-like flower. Zones 5-9.