Yan Hu Suo
Botanical name: Corydalis yanhusuo
Common name: Corydalis rhizome
Literal name translation: extended barbarian rope
Part used in Chinese medicine: rhizome
Major Chinese medicine actions:
Invigorates blood, promotes movement of qi, strongly alleviates pain
Photo 1: Corydalis ambigua; 04/2006; author arudhio; permission under Creative Commons
The original name for the herb we commonly know as Yan Hu Suo, is Xuan Hu Suo, or "dark barbarian rope". The name was changed during the reign of Xuan Ye, an emperor during the early Qing dynasty. During this time the characters of his name, "xuan" and "ye", were taboo and could not be used for any other purpose. "Xuan" was changed to "Yan" in the herb name and Yan Hu Suo has remained the most commonly used name for the herb, though occasionally the original name may be referred to.
Corydalis is a genus containing over 300 species of plants indigenous to many different parts of the world, most of which are known medicinally for their use in the treatment of pain and many which are cultivated in gardens for their pretty flowers and foliage. There are several species which are acceptable for use in Chinese medicine, including Corydalis turtschaninovii, C. repens, C. ambigua (pictured above), and C. glaucencens.
The plant is native to northern China, Siberia, and Japan, growing in the mix of sun and shade at the edge of forests and woodlands.
Growing and Propagation
The plant grows to about 8 inches high and does best in loamy, well-drained soil with adequate moisture. It prefers a part shade environment, though can withstand full sun. When propagating by seed, it is best sown as soon as the seed is ripe as it quickly looses its viability as it dries. The seed should be sown thinly so the seedlings are not disturbed in the first year. Keeping them moist during the germination time is essential, and they will generally sprout within 1-3 months. The seedlings only produce 1 leaf during their first growing year, and they require regular fertilization to ensure a good survival rate. Seedlings can be transplanted to a permanent place in the garden during their dormant period, after their second year of growth.
Harvesting and Preparation
For medicinal use, good quality Yan Hu Suo are dried tubers that are light yellow in color, hard and large. They are cut into slices showing a glossy, wax-like cross section. Small rhizomes with a grayish yellow cross section are considered poor quality.