Codonopsis pilosula aka Bellflower

Codonopsis pilosula is a perennial climber in the bellflower family, Campanulaceae. Its common names include dang shen and bellflower. It comes from temperate Asia, from Mongolia through China to Korea. Its range also includes parts of the Russian Far East. In the wild, it grows in thick scrub and along streambanks. It also grows beneath trees at the edges of woods.

This plant reaches about 5.6 feet [1.7 metres] in height. It has tuberous roots and climbs by twining through nearby plants. Its stems can also scramble over surrounding growth. This habit suits a woodland edge with plants for support. It flowers from June to August. Each flower has both male and female organs. Insects pollinate the flowers, and seeds ripen from August to September. A raised bank can make the flowers easier to see.

Give it fertile soil that drains well but stays moist. Sandy or loamy soil suits it. It accepts mildly acid to neutral soil, with a preference for slight acidity. Grow it in partial shade or full sun. In full sun, the soil must stay moist through the growing season. PFAF lists it for USDA zones 5–9. Dormant plants withstand cold, but fresh spring shoots can suffer frost damage. A site shielded from early morning sun helps protect this growth.

Roots dislike disturbance, so choose a lasting planting spot early. Sow seed on the surface of ericaceous compost in spring or early summer. Keep it in a greenhouse and do not let it dry. Germination takes one to six weeks at 68°F [20°C]. Move seedlings into separate pots once large enough to handle. Keep them under glass through their first winter. Plant them out in late spring or early summer. Slugs can damage young plants, which need protection until established. Spring division is possible, but handle the roots with care.

The roots are edible, either raw or cooked. They also have a long role in Chinese herbal medicine. Traditional use centres on the root as a tonic. PFAF reports root compounds including saponins, triterpenes and steroids. Such use does not establish that every claimed effect is proven. PFAF records no known hazards, but this does not confirm pet safety. The same source does not flag the species as weedy.