Isatis indigotica Seeds | Woad Root
LATIN NAME: Isatis indigotica
COMMON NAME: Isatidis Radix, Ban Lan Gen, Indigo Woad
Plant Profile
Isatis indigotica, commonly known as Isatidis Radix, is an upright, branching, biennial in the mustard family (Brassicaceae), native to warm regions of the Mediterranean and the east, while it has been cultivated for its blue dye. The flowers pull in pollinating insects, which quietly widens its usefulness in the garden. Put simply, this is a rewarding species for anyone willing to give it a suitable spot.
Science & Biotechnology
Ban lan gen and its leaf (da qing ye, the historical source of indigo dye) share the bisindole alkaloids indigo and indirubin. In cell culture, indirubin inhibits replication of Japanese encephalitis virus with an IC50 around 14 micrograms per millilitre, apparently by blocking viral attachment, and protects mice from lethal challenge; related work shows it restores interferon signalling through the MAVS pathway in influenza-infected cells. Indirubin also inhibits cyclin-dependent kinases and GSK-3, and a derivative, meisoindigo, has been used clinically in China for chronic myeloid leukaemia. It remains one of the clearest examples of a dye-plant alkaloid becoming a drug lead.
Isatis indigotica sits in the mustard family, a group that keeps botanists, horticulturists and plant breeders busy with questions of classification, adaptation and ornamental potential. Isatidis radix and woad have a real and distinguished place in research. Species like this one find a second career as research material, especially in propagation and breeding work.
Uses & Benefits
Beyond its ornamental appeal, Isatidis Radix has the practical versatility that makes a plant worth growing from seed year after year. Woad is a tall, upright biennial of open fields and disturbed ground, where its bright-yellow flowers light up early summer. Its flowers feed bees and insects of spring, and its tall, branching growth gives a fine cover to small creatures, while its deep taproot helps to break up compacted soil. To raise woad, sow seeds in pots of moist, open soil in a sunny, cool place, keep them gently watered, and grow little plants on in the sun. After the first season it asks for very little beyond a place that suits it.
Woad is doubly famous: its leaves dyed Europe blue before indigo, and its root, Ban Lan Gen, with the leaf Da Qing Ye, is among the most-used Chinese antiviral folk herbs, taken in granules at the first sign of colds across East Asia.
Growing from Seed
Raising Isatidis Radix from seed is straightforward. Fill a pot with a light seed compost, sow evenly on the surface, cover thinly and stand it somewhere warm, bright and evenly moist. When the young plants are big enough to handle, space them into pots or a nursery row and let them size up before their final move.
Our Take
Isatidis Radix repays a little patience at sowing time with plenty of garden presence later.
Related Reading
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