- Botanical name: Astragalus membranaceus
- Common name: Astragalus, Milk-vetch root
- Family: Fabaceae, pea family
- Part used in Chinese medicine: root
- Major Chinese medicine actions:
- Tonifies Spleen and Lung qi, raises yang qi, tonifies
wei qi, promotes urination
Photo Credits: (top to bottom)
Photo 1: Image source unavailable
Photo 2: Image source unavailable
Photo 3: Astragalus membranaceus; 06/2007; author Doronenko; permission under GFDL
Growing and Propagation
In order to germinate seeds, it is helpful to score the thick outer shell with a file or sandpaper and then soak the seeds overnight in warm water. They can be planted directly into the garden in deep, sandy, well-drained soil in spring. It is best not to grow them in containers as it can cause the roots to deform and stunt plant growth.
Planting in normal to poor garden soil is best, though it should be somewhat alkaline, with good drainage. The addition of compost or manure to the soil is not advisable, as it will cause the leafy part of the plant to overgrow. Plants grow 10-24 inches tall, with racemes of yellow pea-like flowers appearing in early summer, followed by pendulous pods up to six inches long. Astragalus membranaceus is hardy in USDA zones 7 to 9.
Harvesting and Preparation
For medicinal use, roots should be harvested in the fall and when the plant is at full maturity, between 4-7 years old. The lateral smaller rootlets are removed, the crown cut off, and the main root is dried in the sun until about 60-70% dry. Roots are then cut lengthwise into pieces and dried completely. For medicinal purposes, cultivated roots are considered to be of better quality than wild harvested roots.
Huang Qi is commonly used in its raw form, but may be prepared as dry-fried (chao huang qi), wine-fried (jiu chao huang qi), or honey-fried (mi zhi huang qi. Good quality roots are long, thick, and unbranched. A cross section should show a yellowish white cortex with a fresh yellow center. The texture of the root is soft and the taste should be sweet.
The genus Astragalus contains more that 2,000 species and is the largest genus group of flowering plants. In its native environment in China, Astragalus membranaceus grows along the edges of forests and in thin open woods where the sun is dappled. It can be difficult to germinate the seeds, but once sprouted, the plant is relatively easy to grow.