Codonopsis lanceolata Seeds | Bonnet Bellflower
LATIN NAME: Codonopsis lanceolata
COMMON NAME: Bonnet Bellflower, Lance Asiabell
Plant Profile
Codonopsis lanceolata is a twining herbaceous perennial of the bellflower family with a swollen, carrot-shaped storage root that can thicken to the size of a wrist. It is dug in its second autumn, before it turns woody. Freshly cut, it bleeds a milky white latex and darkens quickly, so it is peeled straight into water or a weak brine.
The plant climbs rather than leans. Slender stems twine around a support and carry the vine a metre or more up through surrounding vegetation, and at the ends of the branches the leaves gather into a characteristic cluster of four, the easiest way to recognise the species in the field. The blades are lance-shaped, as the epithet says, and the lower leaves are smaller and set wider apart.
The flowers hang like small bells from the leaf axils, pale greenish outside and marked with purple within, and they open on a nodding stalk. The bell is deep and narrow at the mouth, so the reward is reachable only by a robust insect; bumblebees push in and work the flower from the front, carrying pollen away on their bodies.
Each flower is male first. The anthers shed pollen before the stigma lobes become receptive, and the style then extends so that the receptive surface sits in the path a visiting insect must take. That sequence, protandry, reduces the chance of self-fertilisation.
The fleshy root is a long-standing ingredient in east Asian decoctions, where it is sliced and simmered, often with other roots, and taken as a warming tonic rather than as a remedy for one complaint. The same organ, freshly dug, supplies the vegetable side of the crop. In the garden the vine is grown over a tripod or fence as an ornamental, for its pale bells and autumn colour.
Science & Biotechnology
Codonopsis is a genus of roots, and its chemistry is anchored by a polyacetylene glycoside, lobetyolin, the standard marker compound in quality control across the genus. Beside it sit polysaccharides and the phenylpropanoid glycoside syringin. Lobetyolin is what an analytical laboratory measures when it needs one number for a batch of root.
Lobetyolin and its relatives have an unstable backbone and are not cheap to make by synthesis. Cultures of transformed hairy roots, raised with Agrobacterium rhizogenes, have been used to study their accumulation, and cell and organ cultures of Codonopsis are a standard route for testing how light, sugar supply and precursor feeding shift the yield of the marker compounds.
Uses & Benefits
Because the root carries strong fibres, the traditional handling is physical rather than thermal: it is split lengthwise, soaked, then beaten with a wooden mallet until the flesh softens and the fibres loosen, after which it is rinsed. From there it is marinated in a chilli paste or a soy dressing, or brushed with oil and grilled over a low fire until tender. It also goes into a long-simmered broth, and sliced roots are preserved in a salted, fermented preparation for winter.
Growing from Seed
Seed-raised Codonopsis is variable and the root is the product, so clonal propagation matters. Shoot tips and axillary buds establish on a salt medium with a cytokinin and produce plantlets that can be rooted and hardened off, and somatic embryos have been raised from leaf explants in the genus.
Sow the small seed on the surface of a fine, moisture-holding mix and cover it only lightly, because it needs light and a steady supply of water to sprout. Prick the seedlings out when they have two true leaves and the first sign of the lance-shaped blade, and grow them on in deep pots, since a taproot that coils will fork.
Plant out 25 to 30 centimetres apart with a support the vines can find at once, in light shade and a soil that stays moist but never waterlogged. Water steadily through the first season and mulch to keep the surface cool. Lift the roots in the second autumn, after the stems have withered, with a fork set well back from the crown so the root is not speared. Wash aphids off the soft tips rather than spraying, and watch for rot in any hollow that holds water.
Our Take
The bonnet bellflower is worth growing for the root alone, but it also earns its place on a fence. If you like the genus, the medicinal codonopsis (Codonopsis pilosula) is grown the same way for a sweeter root, the clustered bellflower (Campanula glomerata) gives you the family as a border perennial rather than a vine, and the wider bellflower family (Campanulaceae) is a good place to browse for companions.
Related Reading
If Bonnet Bellflower appeals to you, these related plants are worth a look: